Subtract from 100 or 1000

All from 9, and the last from 10 — no borrowing at all.

The question

What is 1000 − 357?

The trick

Subtract every digit from 9, except the very last one, which you subtract from 10.

Worked example

19 − 3 = 6
29 − 5 = 4
310 − 7 = 3
4Read it off: 643

So: 643

Remember it like this

All from nine, and the last from ten. Say it out loud — it rhymes, and that is the whole method.

In the exam

If the number has fewer digits than the power of ten, pad it with leading zeros first. 1000 − 95 → treat it as 095 → 9−0, 9−9, 10−5 → 905. Padding is what people forget.

Why it works

1000 is 999 + 1. Subtracting from 999 never needs borrowing because every digit is a 9, and the spare 1 is what turns the final column into a 10.

Explain this to my childGet the words to teach it, in your language

Try it yourself

0/4 correct

1
1000 − 482
1000 − 482
2
1000 − 736
1000 − 736
3
100 − 67
100 − 67
4
1000 − 905
1000 − 905