Skill 2B: Subtracting a 3-digit number from a 4-digit number
Use column subtraction with exchanging to take a 3-digit number from a 4-digit number.
Download the sheets
Each file is an editable Word document (.docx) with 25 questions in five columns. It opens in Word, Google Docs, Pages and LibreOffice, so you can change questions or add working space before printing.
Column subtraction needs an exchange whenever the top digit is smaller than the digit underneath. When there is a 0 in the way, the exchange passes across it.
Example 1
A 4-digit number take away a 3-digit number
7,205 − 468
Estimate first: 7,200 − 500 = 6,700, so the answer should be close to 6,700.
Write the larger number on top and line the digits up by place value. Start on the right. The small crossed-out digits show the exchanges.
76
211
09
515
−
4
6
8
6
7
3
7
Work from right to left:
ones: 15 − 8 = 7. 5 is smaller than 8 and the tens column is 0, so exchange across the zero: take 1 from the hundreds column, leave 9 in each zero column and make 15 here.
tens: 9 − 6 = 3.
hundreds: 11 − 4 = 7. 1 (after lending 1 away) is smaller than 4, so exchange: take 1 from the thousands column to make 11.
thousands: 6 − 0 = 6.
The answer is 6,737. Check by adding back: 6,737 + 468 = 7,205.
Answer: 6,737
Top tips
The bigger number always goes on top.
Check with the inverse: add your answer to the number you took away.
A 0 in the top row means you have to exchange from further along.
Watch out for
Taking the smaller digit from the larger one in a column, whichever way round they are.
Not changing the digit you took from.
Try some questions
These are from the worksheet. Work each one out, then open it to check.