Use the formula subtract ALL FROM 9 AND THE LAST FROM 10 to
perform instant subtractions.

For example 1000 - 357 = 643

We simply take each figure in 357 from 9 and the last figure from 10.

So the answer is 1000 - 357 = 643

And thats all there is to it!

This always works for subtractions from numbers consisting of a 1 followed by noughts: 100; 1000; 10,000 etc.

Similarly 10,000 - 1049 = 8951

For 1000 - 83, in which we have more zeros than figures in the numbers being subtracted, we simply suppose 83 is 083.
So 1000 - 83 becomes 1000 - 083 = 917

Try some yourself:

1) 1000 - 777 =

2) 1000 - 283 =

3) 1000 - 505 =

4) 10,000 - 2345 =

5) 10,000 - 9876 =

6) 10,000 - 1011 =

7) 100 - 57 =

8) 1000 - 57 =

9) 10,000 - 321 =

10) 10,000 - 38 =