Solved Word Problems on Prime and Composite Numbers in Grade 4

Master prime and composite numbers through word problems: identifying primes, finding composites, understanding divisibility, and recognizing number properties in real-world contexts through these 5 detailed exercises.

Word Problem Solutions: 1 to 3
1 Word Problem: Prime Identification
Word Problem 1
Emma has 73 marbles. She wants to arrange them in equal rows with no marbles left over. How many different ways can she arrange the marbles? Is 73 prime or composite?
Definition:

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

Method:
  1. Find all factors of the number (arrangement options)
  2. Count the total number of factors
  3. Determine if it's prime (2 factors) or composite (more than 2)
  4. Answer the question about arrangement options
Marble count
73
Factors
1, 73
Arrangement options
1×73 or 73×1
Step 1: Find factors of 73

Factors of 73: 1, 73

Step 2: Interpret arrangement options

Option 1: 1 row of 73 marbles (1×73)

Option 2: 73 rows of 1 marble each (73×1)

Step 3: Determine if 73 is prime or composite

Since 73 has exactly 2 factors (1 and 73), it's prime

Step 4: Answer the question

Emma can arrange her marbles in only 2 ways: 1 row of 73 marbles or 73 rows of 1 marble each

Step 5: Check divisibility by 1

73 ÷ 1 = 73 remainder 0 → 1 is a factor

Step 6: Check divisibility by 2

73 ÷ 2 = 36 remainder 1 → 2 is not a factor

Step 7: Check divisibility by 3

73 ÷ 3 = 24 remainder 1 → 3 is not a factor

Step 8: Check divisibility by 4

73 ÷ 4 = 18 remainder 1 → 4 is not a factor

Step 9: Check divisibility by 5

73 ÷ 5 = 14 remainder 3 → 5 is not a factor

Step 10: Check divisibility by 6

73 ÷ 6 = 12 remainder 1 → 6 is not a factor

Step 11: Check divisibility by 7

73 ÷ 7 = 10 remainder 3 → 7 is not a factor

Step 12: Check divisibility by 8

73 ÷ 8 = 9 remainder 1 → 8 is not a factor

Step 13: Check divisibility by 9

73 ÷ 9 = 8 remainder 1 → 9 is not a factor

Step 14: Check divisibility by 10

73 ÷ 10 = 7 remainder 3 → 10 is not a factor

Step 15: Check divisibility by 11

73 ÷ 11 = 6 remainder 7 → 11 is not a factor

Step 16: Check divisibility by 12

73 ÷ 12 = 6 remainder 1 → 12 is not a factor

Step 17: Check divisibility by 13

73 ÷ 13 = 5 remainder 8 → 13 is not a factor

Step 18: Check divisibility by 14

73 ÷ 14 = 5 remainder 3 → 14 is not a factor

Step 19: Check divisibility by 15

73 ÷ 15 = 4 remainder 13 → 15 is not a factor

Step 20: Check divisibility by 16

73 ÷ 16 = 4 remainder 9 → 16 is not a factor

Step 21: Check divisibility by 17

73 ÷ 17 = 4 remainder 5 → 17 is not a factor

Step 22: Check divisibility by 18

73 ÷ 18 = 4 remainder 1 → 18 is not a factor

Step 23: Check divisibility by 19

73 ÷ 19 = 3 remainder 16 → 19 is not a factor

Step 24: Check divisibility by 20

73 ÷ 20 = 3 remainder 13 → 20 is not a factor

Step 25: Check divisibility by 21

73 ÷ 21 = 3 remainder 10 → 21 is not a factor

Step 26: Check divisibility by 22

73 ÷ 22 = 3 remainder 7 → 22 is not a factor

Step 27: Check divisibility by 23

73 ÷ 23 = 3 remainder 4 → 23 is not a factor

Step 28: Check divisibility by 24

73 ÷ 24 = 3 remainder 1 → 24 is not a factor

Step 29: Check divisibility by 25

73 ÷ 25 = 2 remainder 23 → 25 is not a factor

Step 30: Check divisibility by 26

73 ÷ 26 = 2 remainder 21 → 26 is not a factor

Step 31: Check divisibility by 27

73 ÷ 27 = 2 remainder 19 → 27 is not a factor

Step 32: Check divisibility by 28

73 ÷ 28 = 2 remainder 17 → 28 is not a factor

Step 33: Check divisibility by 29

73 ÷ 29 = 2 remainder 15 → 29 is not a factor

Step 34: Check divisibility by 30

73 ÷ 30 = 2 remainder 13 → 30 is not a factor

Step 35: Check divisibility by 31

73 ÷ 31 = 2 remainder 11 → 31 is not a factor

Step 36: Check divisibility by 32

73 ÷ 32 = 2 remainder 9 → 32 is not a factor

Step 37: Check divisibility by 33

73 ÷ 33 = 2 remainder 7 → 33 is not a factor

Step 38: Check divisibility by 34

73 ÷ 34 = 2 remainder 5 → 34 is not a factor

Step 39: Check divisibility by 35

73 ÷ 35 = 2 remainder 3 → 35 is not a factor

Step 40: Check divisibility by 36

73 ÷ 36 = 2 remainder 1 → 36 is not a factor

Step 41: Check divisibility by 37

73 ÷ 37 = 1 remainder 36 → 37 is not a factor

Step 42: Check divisibility by 38

73 ÷ 38 = 1 remainder 35 → 38 is not a factor

Step 43: Check divisibility by 39

73 ÷ 39 = 1 remainder 34 → 39 is not a factor

Step 44: Check divisibility by 40

73 ÷ 40 = 1 remainder 33 → 40 is not a factor

Step 45: Check divisibility by 41

73 ÷ 41 = 1 remainder 32 → 41 is not a factor

Step 46: Check divisibility by 42

73 ÷ 42 = 1 remainder 31 → 42 is not a factor

Step 47: Check divisibility by 43

73 ÷ 43 = 1 remainder 30 → 43 is not a factor

Step 48: Check divisibility by 44

73 ÷ 44 = 1 remainder 29 → 44 is not a factor

Step 49: Check divisibility by 45

73 ÷ 45 = 1 remainder 28 → 45 is not a factor

Step 50: Check divisibility by 46

73 ÷ 46 = 1 remainder 27 → 46 is not a factor

Step 51: Check divisibility by 47

73 ÷ 47 = 1 remainder 26 → 47 is not a factor

Step 52: Check divisibility by 48

73 ÷ 48 = 1 remainder 25 → 48 is not a factor

Step 53: Check divisibility by 49

73 ÷ 49 = 1 remainder 24 → 49 is not a factor

Step 54: Check divisibility by 50

73 ÷ 50 = 1 remainder 23 → 50 is not a factor

Step 55: Check divisibility by 51

73 ÷ 51 = 1 remainder 22 → 51 is not a factor

Step 56: Check divisibility by 52

73 ÷ 52 = 1 remainder 21 → 52 is not a factor

Step 57: Check divisibility by 53

73 ÷ 53 = 1 remainder 20 → 53 is not a factor

Step 58: Check divisibility by 54

73 ÷ 54 = 1 remainder 19 → 54 is not a factor

Step 59: Check divisibility by 55

73 ÷ 55 = 1 remainder 18 → 55 is not a factor

Step 60: Check divisibility by 56

73 ÷ 56 = 1 remainder 17 → 56 is not a factor

Step 61: Check divisibility by 57

73 ÷ 57 = 1 remainder 16 → 57 is not a factor

Step 62: Check divisibility by 58

73 ÷ 58 = 1 remainder 15 → 58 is not a factor

Step 63: Check divisibility by 59

73 ÷ 59 = 1 remainder 14 → 59 is not a factor

Step 64: Check divisibility by 60

73 ÷ 60 = 1 remainder 13 → 60 is not a factor

Step 65: Check divisibility by 61

73 ÷ 61 = 1 remainder 12 → 61 is not a factor

Step 66: Check divisibility by 62

73 ÷ 62 = 1 remainder 11 → 62 is not a factor

Step 67: Check divisibility by 63

73 ÷ 63 = 1 remainder 10 → 63 is not a factor

Step 68: Check divisibility by 64

73 ÷ 64 = 1 remainder 9 → 64 is not a factor

Step 69: Check divisibility by 65

73 ÷ 65 = 1 remainder 8 → 65 is not a factor

Step 70: Check divisibility by 66

73 ÷ 66 = 1 remainder 7 → 66 is not a factor

Step 71: Check divisibility by 67

73 ÷ 67 = 1 remainder 6 → 67 is not a factor

Step 72: Check divisibility by 68

73 ÷ 68 = 1 remainder 5 → 68 is not a factor

Step 73: Check divisibility by 69

73 ÷ 69 = 1 remainder 4 → 69 is not a factor

Step 74: Check divisibility by 70

73 ÷ 70 = 1 remainder 3 → 70 is not a factor

Step 75: Check divisibility by 71

73 ÷ 71 = 1 remainder 2 → 71 is not a factor

Step 76: Check divisibility by 72

73 ÷ 72 = 1 remainder 1 → 72 is not a factor

Step 77: Check divisibility by 73

73 ÷ 73 = 1 remainder 0 → 73 is a factor

Factors of 73: 1, 73 (exactly 2 factors) → 73 is prime
Final answer:

Emma can arrange her 73 marbles in 1 row of 73 marbles or 73 rows of 1 marble each. The number 73 is prime because it has exactly two factors: 1 and 73.

Applied rules:

• Prime Application: Prime numbers limit arrangement options

• Real-world connection: Equal arrangement requires understanding factors

• Verification: Confirm that arrangements use all items

2 Word Problem: Composite Identification
Word Problem 2
A teacher has 60 students and wants to divide them into equal groups for a project with no students left over. How many different ways can she divide the students? Is 60 prime or composite?
Definition:

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

Student count
60
Factors
1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, 60
Grouping options
12 different ways
Step 1: Find all factors of 60

Factors of 60: 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, 60

Step 2: List all possible groupings

1 group of 60 students (1×60)

2 groups of 30 students (2×30)

3 groups of 20 students (3×20)

4 groups of 15 students (4×15)

5 groups of 12 students (5×12)

6 groups of 10 students (6×10)

10 groups of 6 students (10×6)

12 groups of 5 students (12×5)

15 groups of 4 students (15×4)

20 groups of 3 students (20×3)

30 groups of 2 students (30×2)

60 groups of 1 student (60×1)

Step 3: Determine if 60 is prime or composite

Since 60 has 12 factors (>2), it's composite

Step 4: Answer the question

The teacher has 12 different ways to divide 60 students into equal groups

Step 5: Check divisibility by 1

60 ÷ 1 = 60 remainder 0 → 1 is a factor

Step 6: Check divisibility by 2

60 ÷ 2 = 30 remainder 0 → 2 is a factor

Step 7: Check divisibility by 3

60 ÷ 3 = 20 remainder 0 → 3 is a factor

Step 8: Check divisibility by 4

60 ÷ 4 = 15 remainder 0 → 4 is a factor

Step 9: Check divisibility by 5

60 ÷ 5 = 12 remainder 0 → 5 is a factor

Step 10: Check divisibility by 6

60 ÷ 6 = 10 remainder 0 → 6 is a factor

Step 11: Check divisibility by 7

60 ÷ 7 = 8 remainder 4 → 7 is not a factor

Step 12: Check divisibility by 8

60 ÷ 8 = 7 remainder 4 → 8 is not a factor

Step 13: Check divisibility by 9

60 ÷ 9 = 6 remainder 6 → 9 is not a factor

Step 14: Check divisibility by 10

60 ÷ 10 = 6 remainder 0 → 10 is a factor

Step 15: Check divisibility by 11

60 ÷ 11 = 5 remainder 5 → 11 is not a factor

Step 16: Check divisibility by 12

60 ÷ 12 = 5 remainder 0 → 12 is a factor

Step 17: Check divisibility by 13

60 ÷ 13 = 4 remainder 8 → 13 is not a factor

Step 18: Check divisibility by 14

60 ÷ 14 = 4 remainder 4 → 14 is not a factor

Step 19: Check divisibility by 15

60 ÷ 15 = 4 remainder 0 → 15 is a factor

Step 20: Check divisibility by 16

60 ÷ 16 = 3 remainder 12 → 16 is not a factor

Step 21: Check divisibility by 17

60 ÷ 17 = 3 remainder 9 → 17 is not a factor

Step 22: Check divisibility by 18

60 ÷ 18 = 3 remainder 6 → 18 is not a factor

Step 23: Check divisibility by 19

60 ÷ 19 = 3 remainder 3 → 19 is not a factor

Step 24: Check divisibility by 20

60 ÷ 20 = 3 remainder 0 → 20 is a factor

Step 25: Check divisibility by 21

60 ÷ 21 = 2 remainder 18 → 21 is not a factor

Step 26: Check divisibility by 22

60 ÷ 22 = 2 remainder 16 → 22 is not a factor

Step 27: Check divisibility by 23

60 ÷ 23 = 2 remainder 14 → 23 is not a factor

Step 28: Check divisibility by 24

60 ÷ 24 = 2 remainder 12 → 24 is not a factor

Step 29: Check divisibility by 25

60 ÷ 25 = 2 remainder 10 → 25 is not a factor

Step 30: Check divisibility by 26

60 ÷ 26 = 2 remainder 8 → 26 is not a factor

Step 31: Check divisibility by 27

60 ÷ 27 = 2 remainder 6 → 27 is not a factor

Step 32: Check divisibility by 28

60 ÷ 28 = 2 remainder 4 → 28 is not a factor

Step 33: Check divisibility by 29

60 ÷ 29 = 2 remainder 2 → 29 is not a factor

Step 34: Check divisibility by 30

60 ÷ 30 = 2 remainder 0 → 30 is a factor

Step 35: Check divisibility by 31

60 ÷ 31 = 1 remainder 29 → 31 is not a factor

Step 36: Check divisibility by 32

60 ÷ 32 = 1 remainder 28 → 32 is not a factor

Step 37: Check divisibility by 33

60 ÷ 33 = 1 remainder 27 → 33 is not a factor

Step 38: Check divisibility by 34

60 ÷ 34 = 1 remainder 26 → 34 is not a factor

Step 39: Check divisibility by 35

60 ÷ 35 = 1 remainder 25 → 35 is not a factor

Step 40: Check divisibility by 36

60 ÷ 36 = 1 remainder 24 → 36 is not a factor

Step 41: Check divisibility by 37

60 ÷ 37 = 1 remainder 23 → 37 is not a factor

Step 42: Check divisibility by 38

60 ÷ 38 = 1 remainder 22 → 38 is not a factor

Step 43: Check divisibility by 39

60 ÷ 39 = 1 remainder 21 → 39 is not a factor

Step 44: Check divisibility by 40

60 ÷ 40 = 1 remainder 20 → 40 is not a factor

Step 45: Check divisibility by 41

60 ÷ 41 = 1 remainder 19 → 41 is not a factor

Step 46: Check divisibility by 42

60 ÷ 42 = 1 remainder 18 → 42 is not a factor

Step 47: Check divisibility by 43

60 ÷ 43 = 1 remainder 17 → 43 is not a factor

Step 48: Check divisibility by 44

60 ÷ 44 = 1 remainder 16 → 44 is not a factor

Step 49: Check divisibility by 45

60 ÷ 45 = 1 remainder 15 → 45 is not a factor

Step 50: Check divisibility by 46

60 ÷ 46 = 1 remainder 14 → 46 is not a factor

Step 51: Check divisibility by 47

60 ÷ 47 = 1 remainder 13 → 47 is not a factor

Step 52: Check divisibility by 48

60 ÷ 48 = 1 remainder 12 → 48 is not a factor

Step 53: Check divisibility by 49

60 ÷ 49 = 1 remainder 11 → 49 is not a factor

Step 54: Check divisibility by 50

60 ÷ 50 = 1 remainder 10 → 50 is not a factor

Step 55: Check divisibility by 51

60 ÷ 51 = 1 remainder 9 → 51 is not a factor

Step 56: Check divisibility by 52

60 ÷ 52 = 1 remainder 8 → 52 is not a factor

Step 57: Check divisibility by 53

60 ÷ 53 = 1 remainder 7 → 53 is not a factor

Step 58: Check divisibility by 54

60 ÷ 54 = 1 remainder 6 → 54 is not a factor

Step 59: Check divisibility by 55

60 ÷ 55 = 1 remainder 5 → 55 is not a factor

Step 60: Check divisibility by 56

60 ÷ 56 = 1 remainder 4 → 56 is not a factor

Step 61: Check divisibility by 57

60 ÷ 57 = 1 remainder 3 → 57 is not a factor

Step 62: Check divisibility by 58

60 ÷ 58 = 1 remainder 2 → 58 is not a factor

Step 63: Check divisibility by 59

60 ÷ 59 = 1 remainder 1 → 59 is not a factor

Step 64: Check divisibility by 60

60 ÷ 60 = 1 remainder 0 → 60 is a factor

Factors of 60: 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, 60 (12 factors total)
Final answer:

The teacher can divide her 60 students into equal groups in 12 different ways. The number 60 is composite because it has more than two factors: 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, and 60.

Applied rules:

• Composite Application: Composite numbers offer many grouping options

• Real-world connection: Dividing students requires understanding factors

• Verification: Confirm that groupings use all students

3 Word Problem: Pattern Recognition
Word Problem 3
A farmer has 97 apple trees. He wants to plant them in equal rows with no trees left over. What are his options for arranging the trees? Is 97 prime or composite?
Definition:

Word problems: Real-world scenarios involving factors and divisibility patterns

Tree count
97
Factors
1, 97
Arrangement options
1×97 or 97×1
Step 1: Find factors of 97

Factors of 97: 1, 97

Step 2: Interpret arrangement options

Option 1: 1 row of 97 trees (1×97)

Option 2: 97 rows of 1 tree each (97×1)

Step 3: Determine if 97 is prime or composite

Since 97 has exactly 2 factors (1 and 97), it's prime

Step 4: Answer the question

The farmer can arrange his trees in only 2 ways: 1 row of 97 trees or 97 rows of 1 tree each

Step 5: Check divisibility by 1

97 ÷ 1 = 97 remainder 0 → 1 is a factor

Step 6: Check divisibility by 2

97 ÷ 2 = 48 remainder 1 → 2 is not a factor

Step 7: Check divisibility by 3

97 ÷ 3 = 32 remainder 1 → 3 is not a factor

Step 8: Check divisibility by 4

97 ÷ 4 = 24 remainder 1 → 4 is not a factor

Step 9: Check divisibility by 5

97 ÷ 5 = 19 remainder 2 → 5 is not a factor

Step 10: Check divisibility by 6

97 ÷ 6 = 16 remainder 1 → 6 is not a factor

Step 11: Check divisibility by 7

97 ÷ 7 = 13 remainder 6 → 7 is not a factor

Step 12: Check divisibility by 8

97 ÷ 8 = 12 remainder 1 → 8 is not a factor

Step 13: Check divisibility by 9

97 ÷ 9 = 10 remainder 7 → 9 is not a factor

Step 14: Check divisibility by 10

97 ÷ 10 = 9 remainder 7 → 10 is not a factor

Step 15: Check divisibility by 11

97 ÷ 11 = 8 remainder 9 → 11 is not a factor

Step 16: Check divisibility by 12

97 ÷ 12 = 8 remainder 1 → 12 is not a factor

Step 17: Check divisibility by 13

97 ÷ 13 = 7 remainder 6 → 13 is not a factor

Step 18: Check divisibility by 14

97 ÷ 14 = 6 remainder 13 → 14 is not a factor

Step 19: Check divisibility by 15

97 ÷ 15 = 6 remainder 7 → 15 is not a factor

Step 20: Check divisibility by 16

97 ÷ 16 = 6 remainder 1 → 16 is not a factor

Step 21: Check divisibility by 17

97 ÷ 17 = 5 remainder 12 → 17 is not a factor

Step 22: Check divisibility by 18

97 ÷ 18 = 5 remainder 7 → 18 is not a factor

Step 23: Check divisibility by 19

97 ÷ 19 = 5 remainder 2 → 19 is not a factor

Step 24: Check divisibility by 20

97 ÷ 20 = 4 remainder 17 → 20 is not a factor

Step 25: Check divisibility by 21

97 ÷ 21 = 4 remainder 13 → 21 is not a factor

Step 26: Check divisibility by 22

97 ÷ 22 = 4 remainder 9 → 22 is not a factor

Step 27: Check divisibility by 23

97 ÷ 23 = 4 remainder 5 → 23 is not a factor

Step 28: Check divisibility by 24

97 ÷ 24 = 4 remainder 1 → 24 is not a factor

Step 29: Check divisibility by 25

97 ÷ 25 = 3 remainder 22 → 25 is not a factor

Step 30: Check divisibility by 26

97 ÷ 26 = 3 remainder 19 → 26 is not a factor

Step 31: Check divisibility by 27

97 ÷ 27 = 3 remainder 16 → 27 is not a factor

Step 32: Check divisibility by 28

97 ÷ 28 = 3 remainder 13 → 28 is not a factor

Step 33: Check divisibility by 29

97 ÷ 29 = 3 remainder 10 → 29 is not a factor

Step 34: Check divisibility by 30

97 ÷ 30 = 3 remainder 7 → 30 is not a factor

Step 35: Check divisibility by 31

97 ÷ 31 = 3 remainder 4 → 31 is not a factor

Step 36: Check divisibility by 32

97 ÷ 32 = 3 remainder 1 → 32 is not a factor

Step 37: Check divisibility by 33

97 ÷ 33 = 2 remainder 31 → 33 is not a factor

Step 38: Check divisibility by 34

97 ÷ 34 = 2 remainder 29 → 34 is not a factor

Step 39: Check divisibility by 35

97 ÷ 35 = 2 remainder 27 → 35 is not a factor

Step 40: Check divisibility by 36

97 ÷ 36 = 2 remainder 25 → 36 is not a factor

Step 41: Check divisibility by 37

97 ÷ 37 = 2 remainder 23 → 37 is not a factor

Step 42: Check divisibility by 38

97 ÷ 38 = 2 remainder 21 → 38 is not a factor

Step 43: Check divisibility by 39

97 ÷ 39 = 2 remainder 19 → 39 is not a factor

Step 44: Check divisibility by 40

97 ÷ 40 = 2 remainder 17 → 40 is not a factor

Step 45: Check divisibility by 41

97 ÷ 41 = 2 remainder 15 → 41 is not a factor

Step 46: Check divisibility by 42

97 ÷ 42 = 2 remainder 13 → 42 is not a factor

Step 47: Check divisibility by 43

97 ÷ 43 = 2 remainder 11 → 43 is not a factor

Step 48: Check divisibility by 44

97 ÷ 44 = 2 remainder 9 → 44 is not a factor

Step 49: Check divisibility by 45

97 ÷ 45 = 2 remainder 7 → 45 is not a factor

Step 50: Check divisibility by 46

97 ÷ 46 = 2 remainder 5 → 46 is not a factor

Step 51: Check divisibility by 47

97 ÷ 47 = 2 remainder 3 → 47 is not a factor

Step 52: Check divisibility by 48

97 ÷ 48 = 2 remainder 1 → 48 is not a factor

Step 53: Check divisibility by 49

97 ÷ 49 = 1 remainder 48 → 49 is not a factor

Step 54: Check divisibility by 50

97 ÷ 50 = 1 remainder 47 → 50 is not a factor

Step 55: Check divisibility by 51

97 ÷ 51 = 1 remainder 46 → 51 is not a factor

Step 56: Check divisibility by 52

97 ÷ 52 = 1 remainder 45 → 52 is not a factor

Step 57: Check divisibility by 53

97 ÷ 53 = 1 remainder 44 → 53 is not a factor

Step 58: Check divisibility by 54

97 ÷ 54 = 1 remainder 43 → 54 is not a factor

Step 59: Check divisibility by 55

97 ÷ 55 = 1 remainder 42 → 55 is not a factor

Step 60: Check divisibility by 56

97 ÷ 56 = 1 remainder 41 → 56 is not a factor

Step 61: Check divisibility by 57

97 ÷ 57 = 1 remainder 40 → 57 is not a factor

Step 62: Check divisibility by 58

97 ÷ 58 = 1 remainder 39 → 58 is not a factor

Step 63: Check divisibility by 59

97 ÷ 59 = 1 remainder 38 → 59 is not a factor

Step 64: Check divisibility by 60

97 ÷ 60 = 1 remainder 37 → 60 is not a factor

Step 65: Check divisibility by 61

97 ÷ 61 = 1 remainder 36 → 61 is not a factor

Step 66: Check divisibility by 62

97 ÷ 62 = 1 remainder 35 → 62 is not a factor

Step 67: Check divisibility by 63

97 ÷ 63 = 1 remainder 34 → 63 is not a factor

Step 68: Check divisibility by 64

97 ÷ 64 = 1 remainder 33 → 64 is not a factor

Step 69: Check divisibility by 65

97 ÷ 65 = 1 remainder 32 → 65 is not a factor

Step 70: Check divisibility by 66

97 ÷ 66 = 1 remainder 31 → 66 is not a factor

Step 71: Check divisibility by 67

97 ÷ 67 = 1 remainder 30 → 67 is not a factor

Step 72: Check divisibility by 68

97 ÷ 68 = 1 remainder 29 → 68 is not a factor

Step 73: Check divisibility by 69

97 ÷ 69 = 1 remainder 28 → 69 is not a factor

Step 74: Check divisibility by 70

97 ÷ 70 = 1 remainder 27 → 70 is not a factor

Step 75: Check divisibility by 71

97 ÷ 71 = 1 remainder 26 → 71 is not a factor

Step 76: Check divisibility by 72

97 ÷ 72 = 1 remainder 25 → 72 is not a factor

Step 77: Check divisibility by 73

97 ÷ 73 = 1 remainder 24 → 73 is not a factor

Step 78: Check divisibility by 74

97 ÷ 74 = 1 remainder 23 → 74 is not a factor

Step 79: Check divisibility by 75

97 ÷ 75 = 1 remainder 22 → 75 is not a factor

Step 80: Check divisibility by 76

97 ÷ 76 = 1 remainder 21 → 76 is not a factor

Step 81: Check divisibility by 77

97 ÷ 77 = 1 remainder 20 → 77 is not a factor

Step 82: Check divisibility by 78

97 ÷ 78 = 1 remainder 19 → 78 is not a factor

Step 83: Check divisibility by 79

97 ÷ 79 = 1 remainder 18 → 79 is not a factor

Step 84: Check divisibility by 80

97 ÷ 80 = 1 remainder 17 → 80 is not a factor

Step 85: Check divisibility by 81

97 ÷ 81 = 1 remainder 16 → 81 is not a factor

Step 86: Check divisibility by 82

97 ÷ 82 = 1 remainder 15 → 82 is not a factor

Step 87: Check divisibility by 83

97 ÷ 83 = 1 remainder 14 → 83 is not a factor

Step 88: Check divisibility by 84

97 ÷ 84 = 1 remainder 13 → 84 is not a factor

Step 89: Check divisibility by 85

97 ÷ 85 = 1 remainder 12 → 85 is not a factor

Step 90: Check divisibility by 86

97 ÷ 86 = 1 remainder 11 → 86 is not a factor

Step 91: Check divisibility by 87

97 ÷ 87 = 1 remainder 10 → 87 is not a factor

Step 92: Check divisibility by 88

97 ÷ 88 = 1 remainder 9 → 88 is not a factor

Step 93: Check divisibility by 89

97 ÷ 89 = 1 remainder 8 → 89 is not a factor

Step 94: Check divisibility by 90

97 ÷ 90 = 1 remainder 7 → 90 is not a factor

Step 95: Check divisibility by 91

97 ÷ 91 = 1 remainder 6 → 91 is not a factor

Step 96: Check divisibility by 92

97 ÷ 92 = 1 remainder 5 → 92 is not a factor

Step 97: Check divisibility by 93

97 ÷ 93 = 1 remainder 4 → 93 is not a factor

Step 98: Check divisibility by 94

97 ÷ 94 = 1 remainder 3 → 94 is not a factor

Step 99: Check divisibility by 95

97 ÷ 95 = 1 remainder 2 → 95 is not a factor

Step 100: Check divisibility by 96

97 ÷ 96 = 1 remainder 1 → 96 is not a factor

Step 101: Check divisibility by 97

97 ÷ 97 = 1 remainder 0 → 97 is a factor

Factors of 97: 1, 97 (exactly 2 factors) → 97 is prime
Final answer:

The farmer can arrange his 97 apple trees in 1 row of 97 trees or 97 rows of 1 tree each. The number 97 is prime because it has exactly two factors: 1 and 97.

Applied rules:

• Prime Application: Prime numbers limit arrangement options

• Real-world connection: Planting arrangements require understanding factors

• Verification: Confirm that arrangements use all trees

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

Prime Number Explanation: Numbers that have exactly two factors: 1 and itself, like building blocks that can't be broken down further

Composite Number Explanation: Numbers that have more than two factors, like group projects made up of smaller numbers

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

Explanation approach:
  1. Explanation 1 (Prime): Take number 13 → factors are 1 and 13 → exactly 2 factors → prime
  2. Explanation 2 (Composite): Take number 15 → factors are 1, 3, 5, 15 → 4 factors → composite
  3. Explanation 3 (Pattern): Notice that all even numbers > 2 are composite
  4. Explanation 4 (Application): Prime numbers limit how items can be arranged equally
Explanation 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...

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

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

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

Explanation 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 Explanation: Computer security uses large prime numbers to keep passwords and messages safe.

Explanation 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!