4-digit ÷ 2-digit

1Summary 重點摘要

864 ÷ 24 = 36. Estimate the quotient.

2Vocabulary cards Vocabulary

3Step by step Steps

1. Step 1: Set out the divisionWrite the dividend 864 inside the division bracket and the divisor 24 on the left. Start from the digit with the highest place value and work one place at a time.
2. Step 2: Divide the first two digits8 alone is too small, so take the first two digits. How many 24s fit in 86? 24 × 3 = 72 but 24 × 4 = 96 is too big, so the first quotient digit is 3.
3. Step 3: Multiply and subtractMultiply the digit by the divisor: 24 × 3 = 72, then subtract: 86 − 72 = 14. Every remainder must be smaller than the divisor 24, or the digit was chosen too small.
4. Step 4: Bring down the next digitBring down the 4 beside the remainder 14 to make 144. The next quotient digit is written above this digit of the dividend, keeping the columns lined up.
5. Step 5: Try the quotient againHow many 24s in 144? 24 × 6 = 144 exactly, so write 6 and subtract to get 0. The division finishes with no remainder left over.
6. Step 6: Write the answerReading the quotient digits together gives 864 ÷ 24 = 36. The 3 sits above the tens place and the 6 above the ones place, so the answer is thirty-six with remainder 0.
7. Step 7: Check by multiplyingQuotient times divisor should equal the dividend: 36 × 24 = 36 × 20 + 36 × 4 = 720 + 144 = 864. The check matches, so the answer is correct.

4Diagrams Diagrams

5Worked example Example

6Common mistakes Mistakes

7Quick check Quick check

8Recap Recap

• Use long division step by step
• After each trial the remainder must be smaller than the divisor
• Bring down the next digit after every subtraction
• Write 0 in the quotient when a place cannot be divided
• Check: quotient × divisor + remainder = dividend