How to see it
You cannot take 7 from 3, so borrow. But the tens and hundreds are zero, with nothing to lend. So go left until you find something to borrow from, the 5. Take one thousand, which is ten hundreds. Pass one hundred on to the tens as ten tens. Pass one ten on to the units, as ten units. Now each column has plenty.
A worked example
Units: 13 take 7 is 6. Tens: 9 take 4 is 5. Hundreds: 9 take 8 is 1. Thousands: 4 take 1 is 3. 3,156. Check by adding: 3,156 plus 1,847 is 5,003.
The common mistake: subtracting the smaller digit from the bigger
The trap is saying "7 take 3 is 4" because you cannot do it the right way round. Do that in every column and you get 4,844. You are not allowed to swap them. That is what borrowing is for.
Try one
6,002 take away 2,715.
- A4,713
- B3,287
- C4,287
- D3,297
Show the answerHide the answer
Right: B, 3,287
Always check with the add.