Solved Test Exercises on Prime and Composite Numbers in Grade 4

Master prime and composite numbers through test exercises: identifying primes, finding composites, understanding divisibility, and recognizing number properties through these 5 detailed exercises.

Test Exercise Solutions: 1 to 3
1 Test Exercise: Prime Identification
Test Exercise 1
Is 107 a prime number? Show all your work and explain your reasoning.
Definition:

Prime Number: A number greater than 1 that has exactly two factors: 1 and itself

Method:
  1. Start with 1 and check if it divides the number evenly
  2. Check 2, 3, 4, 5, up to the number itself
  3. List all numbers that divide evenly
  4. Count the total factors
  5. If exactly 2 factors exist, it's prime
Number
107
Factors
1, 107
Count
2 factors
Step 1: Check divisibility by 1

107 ÷ 1 = 107 remainder 0 → 1 is a factor

Step 2: Check divisibility by 2

107 ÷ 2 = 53 remainder 1 → 2 is not a factor

Step 3: Check divisibility by 3

107 ÷ 3 = 35 remainder 2 → 3 is not a factor

Step 4: Check divisibility by 4

107 ÷ 4 = 26 remainder 3 → 4 is not a factor

Step 5: Check divisibility by 5

107 ÷ 5 = 21 remainder 2 → 5 is not a factor

Step 6: Check divisibility by 6

107 ÷ 6 = 17 remainder 5 → 6 is not a factor

Step 7: Check divisibility by 7

107 ÷ 7 = 15 remainder 2 → 7 is not a factor

Step 8: Check divisibility by 8

107 ÷ 8 = 13 remainder 3 → 8 is not a factor

Step 9: Check divisibility by 9

107 ÷ 9 = 11 remainder 8 → 9 is not a factor

Step 10: Check divisibility by 10

107 ÷ 10 = 10 remainder 7 → 10 is not a factor

Step 11: Check divisibility by 11

107 ÷ 11 = 9 remainder 8 → 11 is not a factor

Step 12: Check divisibility by 12

107 ÷ 12 = 8 remainder 11 → 12 is not a factor

Step 13: Check divisibility by 13

107 ÷ 13 = 8 remainder 3 → 13 is not a factor

Step 14: Check divisibility by 14

107 ÷ 14 = 7 remainder 9 → 14 is not a factor

Step 15: Check divisibility by 15

107 ÷ 15 = 7 remainder 2 → 15 is not a factor

Step 16: Check divisibility by 16

107 ÷ 16 = 6 remainder 11 → 16 is not a factor

Step 17: Check divisibility by 17

107 ÷ 17 = 6 remainder 5 → 17 is not a factor

Step 18: Check divisibility by 18

107 ÷ 18 = 5 remainder 17 → 18 is not a factor

Step 19: Check divisibility by 19

107 ÷ 19 = 5 remainder 12 → 19 is not a factor

Step 20: Check divisibility by 20

107 ÷ 20 = 5 remainder 7 → 20 is not a factor

Step 21: Check divisibility by 21

107 ÷ 21 = 5 remainder 2 → 21 is not a factor

Step 22: Check divisibility by 22

107 ÷ 22 = 4 remainder 19 → 22 is not a factor

Step 23: Check divisibility by 23

107 ÷ 23 = 4 remainder 15 → 23 is not a factor

Step 24: Check divisibility by 24

107 ÷ 24 = 4 remainder 11 → 24 is not a factor

Step 25: Check divisibility by 25

107 ÷ 25 = 4 remainder 7 → 25 is not a factor

Step 26: Check divisibility by 26

107 ÷ 26 = 4 remainder 3 → 26 is not a factor

Step 27: Check divisibility by 27

107 ÷ 27 = 3 remainder 26 → 27 is not a factor

Step 28: Check divisibility by 28

107 ÷ 28 = 3 remainder 23 → 28 is not a factor

Step 29: Check divisibility by 29

107 ÷ 29 = 3 remainder 20 → 29 is not a factor

Step 30: Check divisibility by 30

107 ÷ 30 = 3 remainder 17 → 30 is not a factor

Step 31: Check divisibility by 31

107 ÷ 31 = 3 remainder 14 → 31 is not a factor

Step 32: Check divisibility by 32

107 ÷ 32 = 3 remainder 11 → 32 is not a factor

Step 33: Check divisibility by 33

107 ÷ 33 = 3 remainder 8 → 33 is not a factor

Step 34: Check divisibility by 34

107 ÷ 34 = 3 remainder 5 → 34 is not a factor

Step 35: Check divisibility by 35

107 ÷ 35 = 3 remainder 2 → 35 is not a factor

Step 36: Check divisibility by 36

107 ÷ 36 = 2 remainder 35 → 36 is not a factor

Step 37: Check divisibility by 37

107 ÷ 37 = 2 remainder 33 → 37 is not a factor

Step 38: Check divisibility by 38

107 ÷ 38 = 2 remainder 31 → 38 is not a factor

Step 39: Check divisibility by 39

107 ÷ 39 = 2 remainder 29 → 39 is not a factor

Step 40: Check divisibility by 40

107 ÷ 40 = 2 remainder 27 → 40 is not a factor

Step 41: Check divisibility by 41

107 ÷ 41 = 2 remainder 25 → 41 is not a factor

Step 42: Check divisibility by 42

107 ÷ 42 = 2 remainder 23 → 42 is not a factor

Step 43: Check divisibility by 43

107 ÷ 43 = 2 remainder 21 → 43 is not a factor

Step 44: Check divisibility by 44

107 ÷ 44 = 2 remainder 19 → 44 is not a factor

Step 45: Check divisibility by 45

107 ÷ 45 = 2 remainder 17 → 45 is not a factor

Step 46: Check divisibility by 46

107 ÷ 46 = 2 remainder 15 → 46 is not a factor

Step 47: Check divisibility by 47

107 ÷ 47 = 2 remainder 13 → 47 is not a factor

Step 48: Check divisibility by 48

107 ÷ 48 = 2 remainder 11 → 48 is not a factor

Step 49: Check divisibility by 49

107 ÷ 49 = 2 remainder 9 → 49 is not a factor

Step 50: Check divisibility by 50

107 ÷ 50 = 2 remainder 7 → 50 is not a factor

Step 51: Check divisibility by 51

107 ÷ 51 = 2 remainder 5 → 51 is not a factor

Step 52: Check divisibility by 52

107 ÷ 52 = 2 remainder 3 → 52 is not a factor

Step 53: Check divisibility by 53

107 ÷ 53 = 2 remainder 1 → 53 is not a factor

Step 54: Check divisibility by 54

107 ÷ 54 = 1 remainder 53 → 54 is not a factor

Step 55: Check divisibility by 55

107 ÷ 55 = 1 remainder 52 → 55 is not a factor

Step 56: Check divisibility by 56

107 ÷ 56 = 1 remainder 51 → 56 is not a factor

Step 57: Check divisibility by 57

107 ÷ 57 = 1 remainder 50 → 57 is not a factor

Step 58: Check divisibility by 58

107 ÷ 58 = 1 remainder 49 → 58 is not a factor

Step 59: Check divisibility by 59

107 ÷ 59 = 1 remainder 48 → 59 is not a factor

Step 60: Check divisibility by 60

107 ÷ 60 = 1 remainder 47 → 60 is not a factor

Step 61: Check divisibility by 61

107 ÷ 61 = 1 remainder 46 → 61 is not a factor

Step 62: Check divisibility by 62

107 ÷ 62 = 1 remainder 45 → 62 is not a factor

Step 63: Check divisibility by 63

107 ÷ 63 = 1 remainder 44 → 63 is not a factor

Step 64: Check divisibility by 64

107 ÷ 64 = 1 remainder 43 → 64 is not a factor

Step 65: Check divisibility by 65

107 ÷ 65 = 1 remainder 42 → 65 is not a factor

Step 66: Check divisibility by 66

107 ÷ 66 = 1 remainder 41 → 66 is not a factor

Step 67: Check divisibility by 67

107 ÷ 67 = 1 remainder 40 → 67 is not a factor

Step 68: Check divisibility by 68

107 ÷ 68 = 1 remainder 39 → 68 is not a factor

Step 69: Check divisibility by 69

107 ÷ 69 = 1 remainder 38 → 69 is not a factor

Step 70: Check divisibility by 70

107 ÷ 70 = 1 remainder 37 → 70 is not a factor

Step 71: Check divisibility by 71

107 ÷ 71 = 1 remainder 36 → 71 is not a factor

Step 72: Check divisibility by 72

107 ÷ 72 = 1 remainder 35 → 72 is not a factor

Step 73: Check divisibility by 73

107 ÷ 73 = 1 remainder 34 → 73 is not a factor

Step 74: Check divisibility by 74

107 ÷ 74 = 1 remainder 33 → 74 is not a factor

Step 75: Check divisibility by 75

107 ÷ 75 = 1 remainder 32 → 75 is not a factor

Step 76: Check divisibility by 76

107 ÷ 76 = 1 remainder 31 → 76 is not a factor

Step 77: Check divisibility by 77

107 ÷ 77 = 1 remainder 30 → 77 is not a factor

Step 78: Check divisibility by 78

107 ÷ 78 = 1 remainder 29 → 78 is not a factor

Step 79: Check divisibility by 79

107 ÷ 79 = 1 remainder 28 → 79 is not a factor

Step 80: Check divisibility by 80

107 ÷ 80 = 1 remainder 27 → 80 is not a factor

Step 81: Check divisibility by 81

107 ÷ 81 = 1 remainder 26 → 81 is not a factor

Step 82: Check divisibility by 82

107 ÷ 82 = 1 remainder 25 → 82 is not a factor

Step 83: Check divisibility by 83

107 ÷ 83 = 1 remainder 24 → 83 is not a factor

Step 84: Check divisibility by 84

107 ÷ 84 = 1 remainder 23 → 84 is not a factor

Step 85: Check divisibility by 85

107 ÷ 85 = 1 remainder 22 → 85 is not a factor

Step 86: Check divisibility by 86

107 ÷ 86 = 1 remainder 21 → 86 is not a factor

Step 87: Check divisibility by 87

107 ÷ 87 = 1 remainder 20 → 87 is not a factor

Step 88: Check divisibility by 88

107 ÷ 88 = 1 remainder 19 → 88 is not a factor

Step 89: Check divisibility by 89

107 ÷ 89 = 1 remainder 18 → 89 is not a factor

Step 90: Check divisibility by 90

107 ÷ 90 = 1 remainder 17 → 90 is not a factor

Step 91: Check divisibility by 91

107 ÷ 91 = 1 remainder 16 → 91 is not a factor

Step 92: Check divisibility by 92

107 ÷ 92 = 1 remainder 15 → 92 is not a factor

Step 93: Check divisibility by 93

107 ÷ 93 = 1 remainder 14 → 93 is not a factor

Step 94: Check divisibility by 94

107 ÷ 94 = 1 remainder 13 → 94 is not a factor

Step 95: Check divisibility by 95

107 ÷ 95 = 1 remainder 12 → 95 is not a factor

Step 96: Check divisibility by 96

107 ÷ 96 = 1 remainder 11 → 96 is not a factor

Step 97: Check divisibility by 97

107 ÷ 97 = 1 remainder 10 → 97 is not a factor

Step 98: Check divisibility by 98

107 ÷ 98 = 1 remainder 9 → 98 is not a factor

Step 99: Check divisibility by 99

107 ÷ 99 = 1 remainder 8 → 99 is not a factor

Step 100: Check divisibility by 100

107 ÷ 100 = 1 remainder 7 → 100 is not a factor

Step 101: Check divisibility by 101

107 ÷ 101 = 1 remainder 6 → 101 is not a factor

Step 102: Check divisibility by 102

107 ÷ 102 = 1 remainder 5 → 102 is not a factor

Step 103: Check divisibility by 103

107 ÷ 103 = 1 remainder 4 → 103 is not a factor

Step 104: Check divisibility by 104

107 ÷ 104 = 1 remainder 3 → 104 is not a factor

Step 105: Check divisibility by 105

107 ÷ 105 = 1 remainder 2 → 105 is not a factor

Step 106: Check divisibility by 106

107 ÷ 106 = 1 remainder 1 → 106 is not a factor

Step 107: Check divisibility by 107

107 ÷ 107 = 1 remainder 0 → 107 is a factor

Factors of 107: 1, 107 (exactly 2 factors)
Final answer:

Yes, 107 is a prime number because it has exactly two factors: 1 and 107.

Applied rules:

• Prime Definition: Must have exactly two factors

• Factor Testing: Check divisibility systematically

• Counting: Only 2 factors means it's prime

2 Test Exercise: Composite Identification
Test Exercise 2
Is 108 a composite number? Find all its factors and explain why.
Definition:

Composite Number: A number greater than 1 that has more than two factors

Number
108
Factors
1, 2, 3, 4, 6, 9, 12, 18, 27, 36, 54, 108
Count
12 factors
Step 1: Check divisibility by 1

108 ÷ 1 = 108 remainder 0 → 1 is a factor

Step 2: Check divisibility by 2

108 ÷ 2 = 54 remainder 0 → 2 is a factor

Step 3: Check divisibility by 3

108 ÷ 3 = 36 remainder 0 → 3 is a factor

Step 4: Check divisibility by 4

108 ÷ 4 = 27 remainder 0 → 4 is a factor

Step 5: Check divisibility by 5

108 ÷ 5 = 21 remainder 3 → 5 is not a factor

Step 6: Check divisibility by 6

108 ÷ 6 = 18 remainder 0 → 6 is a factor

Step 7: Check divisibility by 7

108 ÷ 7 = 15 remainder 3 → 7 is not a factor

Step 8: Check divisibility by 8

108 ÷ 8 = 13 remainder 4 → 8 is not a factor

Step 9: Check divisibility by 9

108 ÷ 9 = 12 remainder 0 → 9 is a factor

Step 10: Check divisibility by 10

108 ÷ 10 = 10 remainder 8 → 10 is not a factor

Step 11: Check divisibility by 11

108 ÷ 11 = 9 remainder 9 → 11 is not a factor

Step 12: Check divisibility by 12

108 ÷ 12 = 9 remainder 0 → 12 is a factor

Step 13: Check divisibility by 13

108 ÷ 13 = 8 remainder 4 → 13 is not a factor

Step 14: Check divisibility by 14

108 ÷ 14 = 7 remainder 10 → 14 is not a factor

Step 15: Check divisibility by 15

108 ÷ 15 = 7 remainder 3 → 15 is not a factor

Step 16: Check divisibility by 16

108 ÷ 16 = 6 remainder 12 → 16 is not a factor

Step 17: Check divisibility by 17

108 ÷ 17 = 6 remainder 6 → 17 is not a factor

Step 18: Check divisibility by 18

108 ÷ 18 = 6 remainder 0 → 18 is a factor

Step 19: Check divisibility by 19

108 ÷ 19 = 5 remainder 13 → 19 is not a factor

Step 20: Check divisibility by 20

108 ÷ 20 = 5 remainder 8 → 20 is not a factor

Step 21: Check divisibility by 21

108 ÷ 21 = 5 remainder 3 → 21 is not a factor

Step 22: Check divisibility by 22

108 ÷ 22 = 4 remainder 20 → 22 is not a factor

Step 23: Check divisibility by 23

108 ÷ 23 = 4 remainder 16 → 23 is not a factor

Step 24: Check divisibility by 24

108 ÷ 24 = 4 remainder 12 → 24 is not a factor

Step 25: Check divisibility by 25

108 ÷ 25 = 4 remainder 8 → 25 is not a factor

Step 26: Check divisibility by 26

108 ÷ 26 = 4 remainder 4 → 26 is not a factor

Step 27: Check divisibility by 27

108 ÷ 27 = 4 remainder 0 → 27 is a factor

Step 28: Check divisibility by 28

108 ÷ 28 = 3 remainder 24 → 28 is not a factor

Step 29: Check divisibility by 29

108 ÷ 29 = 3 remainder 21 → 29 is not a factor

Step 30: Check divisibility by 30

108 ÷ 30 = 3 remainder 18 → 30 is not a factor

Step 31: Check divisibility by 31

108 ÷ 31 = 3 remainder 15 → 31 is not a factor

Step 32: Check divisibility by 32

108 ÷ 32 = 3 remainder 12 → 32 is not a factor

Step 33: Check divisibility by 33

108 ÷ 33 = 3 remainder 9 → 33 is not a factor

Step 34: Check divisibility by 34

108 ÷ 34 = 3 remainder 6 → 34 is not a factor

Step 35: Check divisibility by 35

108 ÷ 35 = 3 remainder 3 → 35 is not a factor

Step 36: Check divisibility by 36

108 ÷ 36 = 3 remainder 0 → 36 is a factor

Step 37: Check divisibility by 37

108 ÷ 37 = 2 remainder 34 → 37 is not a factor

Step 38: Check divisibility by 38

108 ÷ 38 = 2 remainder 32 → 38 is not a factor

Step 39: Check divisibility by 39

108 ÷ 39 = 2 remainder 30 → 39 is not a factor

Step 40: Check divisibility by 40

108 ÷ 40 = 2 remainder 28 → 40 is not a factor

Step 41: Check divisibility by 41

108 ÷ 41 = 2 remainder 26 → 41 is not a factor

Step 42: Check divisibility by 42

108 ÷ 42 = 2 remainder 24 → 42 is not a factor

Step 43: Check divisibility by 43

108 ÷ 43 = 2 remainder 22 → 43 is not a factor

Step 44: Check divisibility by 44

108 ÷ 44 = 2 remainder 20 → 44 is not a factor

Step 45: Check divisibility by 45

108 ÷ 45 = 2 remainder 18 → 45 is not a factor

Step 46: Check divisibility by 46

108 ÷ 46 = 2 remainder 16 → 46 is not a factor

Step 47: Check divisibility by 47

108 ÷ 47 = 2 remainder 14 → 47 is not a factor

Step 48: Check divisibility by 48

108 ÷ 48 = 2 remainder 12 → 48 is not a factor

Step 49: Check divisibility by 49

108 ÷ 49 = 2 remainder 10 → 49 is not a factor

Step 50: Check divisibility by 50

108 ÷ 50 = 2 remainder 8 → 50 is not a factor

Step 51: Check divisibility by 51

108 ÷ 51 = 2 remainder 6 → 51 is not a factor

Step 52: Check divisibility by 52

108 ÷ 52 = 2 remainder 4 → 52 is not a factor

Step 53: Check divisibility by 53

108 ÷ 53 = 2 remainder 2 → 53 is not a factor

Step 54: Check divisibility by 54

108 ÷ 54 = 2 remainder 0 → 54 is a factor

Step 55: Check divisibility by 55

108 ÷ 55 = 1 remainder 53 → 55 is not a factor

Step 56: Check divisibility by 56

108 ÷ 56 = 1 remainder 52 → 56 is not a factor

Step 57: Check divisibility by 57

108 ÷ 57 = 1 remainder 51 → 57 is not a factor

Step 58: Check divisibility by 58

108 ÷ 58 = 1 remainder 50 → 58 is not a factor

Step 59: Check divisibility by 59

108 ÷ 59 = 1 remainder 49 → 59 is not a factor

Step 60: Check divisibility by 60

108 ÷ 60 = 1 remainder 48 → 60 is not a factor

Step 61: Check divisibility by 61

108 ÷ 61 = 1 remainder 47 → 61 is not a factor

Step 62: Check divisibility by 62

108 ÷ 62 = 1 remainder 46 → 62 is not a factor

Step 63: Check divisibility by 63

108 ÷ 63 = 1 remainder 45 → 63 is not a factor

Step 64: Check divisibility by 64

108 ÷ 64 = 1 remainder 44 → 64 is not a factor

Step 65: Check divisibility by 65

108 ÷ 65 = 1 remainder 43 → 65 is not a factor

Step 66: Check divisibility by 66

108 ÷ 66 = 1 remainder 42 → 66 is not a factor

Step 67: Check divisibility by 67

108 ÷ 67 = 1 remainder 41 → 67 is not a factor

Step 68: Check divisibility by 68

108 ÷ 68 = 1 remainder 40 → 68 is not a factor

Step 69: Check divisibility by 69

108 ÷ 69 = 1 remainder 39 → 69 is not a factor

Step 70: Check divisibility by 70

108 ÷ 70 = 1 remainder 38 → 70 is not a factor

Step 71: Check divisibility by 71

108 ÷ 71 = 1 remainder 37 → 71 is not a factor

Step 72: Check divisibility by 72

108 ÷ 72 = 1 remainder 36 → 72 is not a factor

Step 73: Check divisibility by 73

108 ÷ 73 = 1 remainder 35 → 73 is not a factor

Step 74: Check divisibility by 74

108 ÷ 74 = 1 remainder 34 → 74 is not a factor

Step 75: Check divisibility by 75

108 ÷ 75 = 1 remainder 33 → 75 is not a factor

Step 76: Check divisibility by 76

108 ÷ 76 = 1 remainder 32 → 76 is not a factor

Step 77: Check divisibility by 77

108 ÷ 77 = 1 remainder 31 → 77 is not a factor

Step 78: Check divisibility by 78

108 ÷ 78 = 1 remainder 30 → 78 is not a factor

Step 79: Check divisibility by 79

108 ÷ 79 = 1 remainder 29 → 79 is not a factor

Step 80: Check divisibility by 80

108 ÷ 80 = 1 remainder 28 → 80 is not a factor

Step 81: Check divisibility by 81

108 ÷ 81 = 1 remainder 27 → 81 is not a factor

Step 82: Check divisibility by 82

108 ÷ 82 = 1 remainder 26 → 82 is not a factor

Step 83: Check divisibility by 83

108 ÷ 83 = 1 remainder 25 → 83 is not a factor

Step 84: Check divisibility by 84

108 ÷ 84 = 1 remainder 24 → 84 is not a factor

Step 85: Check divisibility by 85

108 ÷ 85 = 1 remainder 23 → 85 is not a factor

Step 86: Check divisibility by 86

108 ÷ 86 = 1 remainder 22 → 86 is not a factor

Step 87: Check divisibility by 87

108 ÷ 87 = 1 remainder 21 → 87 is not a factor

Step 88: Check divisibility by 88

108 ÷ 88 = 1 remainder 20 → 88 is not a factor

Step 89: Check divisibility by 89

108 ÷ 89 = 1 remainder 19 → 89 is not a factor

Step 90: Check divisibility by 90

108 ÷ 90 = 1 remainder 18 → 90 is not a factor

Step 91: Check divisibility by 91

108 ÷ 91 = 1 remainder 17 → 91 is not a factor

Step 92: Check divisibility by 92

108 ÷ 92 = 1 remainder 16 → 92 is not a factor

Step 93: Check divisibility by 93

108 ÷ 93 = 1 remainder 15 → 93 is not a factor

Step 94: Check divisibility by 94

108 ÷ 94 = 1 remainder 14 → 94 is not a factor

Step 95: Check divisibility by 95

108 ÷ 95 = 1 remainder 13 → 95 is not a factor

Step 96: Check divisibility by 96

108 ÷ 96 = 1 remainder 12 → 96 is not a factor

Step 97: Check divisibility by 97

108 ÷ 97 = 1 remainder 11 → 97 is not a factor

Step 98: Check divisibility by 98

108 ÷ 98 = 1 remainder 10 → 98 is not a factor

Step 99: Check divisibility by 99

108 ÷ 99 = 1 remainder 9 → 99 is not a factor

Step 100: Check divisibility by 100

108 ÷ 100 = 1 remainder 8 → 100 is not a factor

Step 101: Check divisibility by 101

108 ÷ 101 = 1 remainder 7 → 101 is not a factor

Step 102: Check divisibility by 102

108 ÷ 102 = 1 remainder 6 → 102 is not a factor

Step 103: Check divisibility by 103

108 ÷ 103 = 1 remainder 5 → 103 is not a factor

Step 104: Check divisibility by 104

108 ÷ 104 = 1 remainder 4 → 104 is not a factor

Step 105: Check divisibility by 105

108 ÷ 105 = 1 remainder 3 → 105 is not a factor

Step 106: Check divisibility by 106

108 ÷ 106 = 1 remainder 2 → 106 is not a factor

Step 107: Check divisibility by 107

108 ÷ 107 = 1 remainder 1 → 107 is not a factor

Step 108: Check divisibility by 108

108 ÷ 108 = 1 remainder 0 → 108 is a factor

Factors of 108: 1, 2, 3, 4, 6, 9, 12, 18, 27, 36, 54, 108 (12 factors total)
Final answer:

Yes, 108 is a composite number because it has more than two factors: 1, 2, 3, 4, 6, 9, 12, 18, 27, 36, 54, and 108.

Applied rules:

• Composite Definition: Must have more than two factors

• Factor Pairs: 1×108=108, 2×54=108, 3×36=108, 4×27=108, 6×18=108, 9×12=108

• Counting: More than 2 factors means it's composite

3 Test Exercise: Classification
Test Exercise 3
From the list below, classify each number as prime or composite: 101, 103, 105, 107, 109
Definition:

Classification: Determining if each number is prime or composite by finding its factors

Numbers
101, 103, 105, 107, 109
Factors
List each
Types
P, P, C, P, P
Step 1: Analyze 101

Factors: 1, 101 → Prime (exactly 2 factors)

Step 2: Analyze 103

Factors: 1, 103 → Prime (exactly 2 factors)

Step 3: Analyze 105

Factors: 1, 3, 5, 7, 15, 21, 35, 105 → Composite (8 factors)

Step 4: Analyze 107

Factors: 1, 107 → Prime (exactly 2 factors)

Step 5: Analyze 109

Factors: 1, 109 → Prime (exactly 2 factors)

Step 6: Final classification

Prime: 101, 103, 107, 109 | Composite: 105

Prime: 101, 103, 107, 109 | Composite: 105
Final answer:

Prime numbers: 101, 103, 107, 109 | Composite number: 105

Applied rules:

• Systematic Analysis: Examine each number individually

• Factor Counting: Determine the exact number of factors

• Classification Rules: 2 factors = prime, more than 2 = composite

Test Exercise Concepts & Methods
Prime: 2 Factors | Composite: >2 Factors
Classification Rule
Rule 1
Prime: exactly 2 factors
Prime Definition
Rule 2
Composite: more than 2 factors
Composite Definition
Rule 3
Special: 1 = neither prime nor composite
Special Case
Key definitions:

Prime Number: A number greater than 1 that has exactly two factors: 1 and itself

Composite Number: A number greater than 1 that has more than two factors

Factors: Numbers that divide evenly into another number without leaving a remainder

Test methodology:
  1. Check if number > 1: Prime/composite only applies to numbers greater than 1
  2. Find all factors: Systematically check divisibility from 1 up to the number
  3. Count factors: Tally the total number of factors found
  4. Classify: 2 factors = prime, more than 2 = composite
Tip 1: Even numbers (except 2) are always composite since they're divisible by 2.
Tip 2: Numbers ending in 5 (except 5) are composite since they're divisible by 5.
Tip 3: The number 2 is the only even prime number.
Tip 4: To save time, only test divisors up to the square root of the number.
Common errors: Thinking 1 is prime, missing factors when counting, confusing factors with multiples.
Key concepts: Prime numbers are the building blocks of all numbers, every composite number can be broken down into primes.
Rules for test:

• 1 is neither prime nor composite

• 2 is the smallest and only even prime number

• All primes greater than 2 are odd numbers

• The first few prime numbers: 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109...

• Every composite number has at least one prime factor

Test Exercise Solutions: 4 to 5
4 Test Exercise: Word Problem
Test Exercise 4
Sarah has 113 marbles. She wants to arrange them in equal rows with no marbles left over. What are her options for arranging the marbles? Is 113 prime or composite?
Definition:

Word problems: Real-world situations requiring knowledge of factors and divisibility

Marble count
113
Factors
1, 113
Arrangement options
1×113 or 113×1
Step 1: Find factors of 113

Factors of 113: 1, 113

Step 2: Interpret arrangement options

Option 1: 1 row of 113 marbles (1×113)

Option 2: 113 rows of 1 marble each (113×1)

Step 3: Determine if 113 is prime or composite

Since 113 has exactly 2 factors (1 and 113), it's prime

Step 4: Answer the question

Sarah can arrange the marbles in only 2 ways: 1 row of 113 marbles or 113 rows of 1 marble each

113 is prime, so Sarah has only 2 arrangement options
Final answer:

Sarah can arrange her 113 marbles in 1 row of 113 marbles or 113 rows of 1 marble each. The number 113 is prime because it has exactly two factors: 1 and 113.

Applied rules:

• Prime Application: Prime numbers have limited arrangement options

• Real-world connection: Arranging objects requires understanding factors

• Verification: Confirm that arrangements use all marbles

5 Test Exercise: Pattern Recognition
Test Exercise 5
Find all prime numbers between 110 and 120. List them and explain your reasoning.
Definition:

Range analysis: Systematically checking numbers within a specified range

Range
110-120
Check each
111, 112, 113, 114, 115, 116, 117, 118, 119
Primes
113
Step 1: List numbers 111-119 (excluding 110 and 120)

111, 112, 113, 114, 115, 116, 117, 118, 119

Step 2: Check 111

111 = 3 × 37 → composite

Step 3: Check 112

112 = 16 × 7 → composite

Step 4: Check 113

Factors: 1, 113 → prime

Step 5: Check 114

114 = 6 × 19 → composite

Step 6: Check 115

115 = 5 × 23 → composite

Step 7: Check 116

116 = 4 × 29 → composite

Step 8: Check 117

117 = 9 × 13 → composite

Step 9: Check 118

118 = 2 × 59 → composite

Step 10: Check 119

119 = 7 × 17 → composite

Prime numbers between 110 and 120: 113
Final answer:

The prime number between 110 and 120 is: 113

Applied rules:

• Systematic approach: Check each number in the range individually

• Even number rule: All even numbers > 2 are composite

• Verification: Double-check each classification

Test Concepts and Key Ideas
Prime: 2 Factors | Composite: >2 Factors
Test Classification
Test definitions:

Prime Number Test: Exercises focusing on identifying numbers with exactly two factors

Composite Number Test: Problems focusing on identifying numbers with more than two factors

Classification Test: Activities that require distinguishing between prime and composite numbers

Test approach:
  1. Test 1 (Prime): Take number 109 → factors are 1 and 109 → exactly 2 factors → prime
  2. Test 2 (Composite): Take number 110 → factors are 1, 2, 5, 10, 11, 22, 55, 110 → 8 factors → composite
  3. Test 3 (Pattern): Notice that all even numbers > 2 are composite
  4. Test 4 (Application): Prime numbers limit how items can be arranged equally
Test Tip 1: The first few primes are 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109...

Test Tip 2: All primes > 2 are odd numbers (since even numbers > 2 are divisible by 2)

Test Tip 3: Primes become less frequent as numbers get larger

Test Tip 4: Every composite number can be broken down into prime factors

Test Properties: Prime numbers are like building blocks - everything else is made from them. Composite numbers are like "group projects" made up of smaller prime numbers.

Real-world Test: Computer security uses large prime numbers to keep passwords and messages safe.

Test rules:

• 2 is the only even prime number

• All primes > 2 are odd numbers

• Numbers ending in 5 (except 5) are composite

• Every number > 1 is either prime or composite

• Prime factorization is unique for each number

Questions & Answers

Question: Why is 1 not a prime number? It seems like it should be since it only divides by itself.

Answer: This is a great question that confuses many students!

The definition of a prime number specifically states it must have exactly two different factors: 1 and itself. Since 1 only has one factor (itself), it doesn't meet this requirement.

Think of it like this: prime numbers are special because they can only be arranged in exactly two rectangular ways (1 row or 1 column). The number 1 can only be arranged in one way, so it gets its own special category.

So 1 is neither prime nor composite - it's just special by itself!

Question: How can I quickly tell if a number is prime without checking every single number?

Answer: You can use several smart strategies to make this easier!

  • Check divisibility by small primes first: 2, 3, 5, 7, 11
  • Only check up to the square root: If n is your number, only test divisors up to √n
  • Use divisibility rules: If the sum of digits is divisible by 3, the number is divisible by 3

For example, to check if 109 is prime:

  • It's not even, so not divisible by 2
  • Sum of digits: 1+0+9=10, not divisible by 3
  • Doesn't end in 0 or 5, so not divisible by 5
  • √109 ≈ 10.4, so we only check up to 10
  • Check 7: 109 ÷ 7 = 15 remainder 4 → not divisible
  • Check 10: 109 ÷ 10 = 10 remainder 9 → not divisible

Since we've checked all primes up to √109 and none divide 109, it's prime!

Question: Are there any patterns to help me remember which numbers are prime?

Answer: Yes, there are helpful patterns to recognize prime numbers!

  • All primes > 2 are odd (except 2, which is the only even prime)
  • Primes > 5 end in 1, 3, 7, or 9 (never 0, 2, 4, 5, 6, 8)
  • Primes become less frequent as numbers get larger

The first 25 primes to remember: 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109...

Notice that after 2 and 5, all primes end in 1, 3, 7, or 9!

Question: What's the biggest prime number I need to know for grade 4?

Answer: For grade 4, focus on understanding prime numbers up to about 100, especially the smaller ones!

The most important prime numbers to know are: 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109.

These are the prime numbers you'll encounter most often in problems. As you advance in math, you'll learn about larger primes, but these foundational ones are crucial for understanding factors, multiples, and divisibility.

Question: How do I know when to use prime numbers in real life?

Answer: Prime numbers have many real-life applications, especially in technology!

  • Computer Security: Large prime numbers are used to keep passwords and messages safe online
  • Music: Some musicians use prime numbers to create interesting rhythms
  • Art: Artists sometimes use prime numbers for creating unique patterns
  • Shopping: Understanding factors helps when buying items in packages or groups

Even though you might not use them directly now, prime numbers are fundamental to how computers and the internet work!