Division: The process of splitting a number into equal parts or groups
Dividend: The number being divided (the larger number)
Divisor: The number that divides the dividend (the smaller number)
Quotient: The result of division (how many equal parts/groups)
Remainder: What's left over after division (if any)
3-Digit by 2-Digit Division: Division where the dividend is a 3-digit number (100-999) and the divisor is a 2-digit number (10-99)
Place Value: Position of digits (hundreds, tens, ones) that determines their value
Partial Quotient: The portion of the quotient determined at each step of long division
• Division Relationship: Dividend = Divisor × Quotient + Remainder
• Remainder Rule: Remainder is always less than the divisor
• Division by 1: Any number divided by 1 equals itself
• Zero Division: 0 divided by any non-zero number equals 0
• Division by Zero: Undefined (impossible)
• Inverse Operation: Division is the inverse of multiplication
• Place Value Importance: Work from left to right (hundreds → tens → ones)
• Digit-by-Digit Process: Divide one digit at a time, bringing down next digit
• Estimation: Use rounding to estimate quotient before calculating
- Estimate: Round divisor and dividend to estimate the quotient
- Compare hundreds place: How many times does 2-digit divisor go into hundreds digit?
- If divisor is larger: Combine hundreds and tens digits
- Divide: How many times does divisor go into combined number?
- Multiply: Multiply quotient digit by divisor
- Subtract: Subtract result from current number
- Bring down: Bring down the next digit
- Repeat: Continue with remaining digits
- Check: Verify using: Divisor × Quotient + Remainder = Dividend
\(144 \div 12\)
This is a basic 3-digit by 2-digit division problem where we need to find how many times 12 goes into 144
- Estimate: 144 ÷ 12 ≈ 140 ÷ 10 = 14
- Start with the hundreds and tens: 14 ÷ 12 = 1 remainder 2
- Continue with the ones place
We need to divide 144 by 12
144 ÷ 12 = ?
Round: 144 ≈ 140, 12 ≈ 10
Estimate: 140 ÷ 10 = 14
So the answer should be around 12
How many times does 12 go into 14 (hundreds and tens)?
12 × 1 = 12, 12 × 2 = 24 (too big)
So 12 goes into 14 once (1)
Write 1 above the tens place
1 × 12 = 12
14 - 12 = 2
Bring down the 4
Now we have 24
How many times does 12 go into 24?
12 × 2 = 24
So 12 goes into 24 exactly two times (2)
Write 2 above the ones place
2 × 12 = 24
24 - 24 = 0
No remainder
\(144 \div 12 = 12\) with no remainder
• Estimation: Estimate before calculating to check reasonableness
• Long division pattern: Divide, multiply, subtract, bring down, repeat
• Multiplication check: 12 × 12 = 144 ✓
\(257 \div 13\)
This 3-digit by 2-digit division will have a remainder since 13 doesn't divide evenly into 257
We need to divide 257 by 13
257 ÷ 13 = ?
Round: 257 ≈ 260, 13 ≈ 10
Estimate: 260 ÷ 10 = 26
So the answer should be around 20
How many times does 13 go into 25 (hundreds and tens)?
13 × 1 = 13, 13 × 2 = 26 (too big)
So 13 goes into 25 once (1)
Write 1 above the tens place
1 × 13 = 13
25 - 13 = 12
Bring down the 7
Now we have 127
How many times does 13 go into 127?
13 × 9 = 117, 13 × 10 = 130 (too big)
So 13 goes into 127 nine times (9)
Write 9 above the ones place
9 × 13 = 117
127 - 117 = 10
10 is less than 13, so 10 is our remainder
\(257 \div 13 = 19\) remainder \(10\)
Check: \(19 \times 13 + 10 = 247 + 10 = 257\) ✓
• Division algorithm: Dividend = Divisor × Quotient + Remainder
• Remainder constraint: Remainder must be less than divisor
• Estimation: Use multiplication facts to determine how many times divisor fits
\(308 \div 28\)
This 3-digit by 2-digit division includes a zero in the dividend and will result in a 2-digit quotient
We need to divide 308 by 28
308 ÷ 28 = ?
Round: 308 ≈ 300, 28 ≈ 30
Estimate: 300 ÷ 30 = 10
So the answer should be around 10
How many times does 28 go into 30 (hundreds and tens)?
28 × 1 = 28, 28 × 2 = 56 (too big)
So 28 goes into 30 once (1)
Write 1 above the tens place
1 × 28 = 28
30 - 28 = 2
Bring down the 8
Now we have 28
How many times does 28 go into 28?
28 × 1 = 28
So 28 goes into 28 exactly one time (1)
Write 1 above the ones place
1 × 28 = 28
28 - 28 = 0
No remainder
\(308 \div 28 = 11\) with no remainder
Check: \(11 \times 28 = 308\) ✓
• Handling zeros: Zeros in dividend don't change the process
• Long division: Divide, multiply, subtract, bring down, repeat
• Multiplication check: Verify result by multiplying quotient by divisor
This is a word problem requiring 3-digit by 2-digit division to solve an equal grouping situation
School has 432 students and groups of 18
To find complete groups: 432 ÷ 18 = ?
Round: 432 ≈ 430, 18 ≈ 20
Estimate: 430 ÷ 20 = 21.5
So the answer should be around 24
We need to divide 432 by 18
432 ÷ 18 = ?
How many times does 18 go into 43 (hundreds and tens)?
18 × 2 = 36, 18 × 3 = 54 (too big)
So 18 goes into 43 two times (2)
Write 2 above the tens place
2 × 18 = 36
43 - 36 = 7
Bring down the 2
Now we have 72
How many times does 18 go into 72?
18 × 4 = 72
So 18 goes into 72 exactly four times (4)
Write 4 above the ones place
4 × 18 = 72
72 - 72 = 0
No remainder
24 complete groups can be formed
All students are organized (no remainder)
24 complete groups can be formed.
Check: \(24 \times 18 = 432\) ✓
• Equal grouping: Division to organize items into equal groups
• Real-world context: Interpret the quotient in the problem's context
• Verification: Multiply quotient by divisor to check
This 3-digit by 2-digit division will have a remainder. We need to find the quotient and verify our answer.
We need to divide 563 by 24
563 ÷ 24 = ?
Round: 563 ≈ 560, 24 ≈ 25
Estimate: 560 ÷ 25 = 22.4
So the answer should be around 23
How many times does 24 go into 56 (hundreds and tens)?
24 × 2 = 48, 24 × 3 = 72 (too big)
So 24 goes into 56 two times (2)
Write 2 above the tens place
2 × 24 = 48
56 - 48 = 8
Bring down the 3
Now we have 83
How many times does 24 go into 83?
24 × 3 = 72, 24 × 4 = 96 (too big)
So 24 goes into 83 three times (3)
Write 3 above the ones place
3 × 24 = 72
83 - 72 = 11
11 is less than 24, so 11 is our remainder
Check: 23 × 24 + 11 = 552 + 11 = 563 ✓
Alternative check: 563 ÷ 24 = 23 remainder 11 ✓
\(563 \div 24 = 23\) remainder \(11\)
Check: \(23 \times 24 + 11 = 552 + 11 = 563\) ✓
• Division verification: Always check your answer
• Multiplication facts: Knowing 24 × 23 = 552 helps solve this
• Place value: Work from hundreds to tens to ones