As we know in decimal system ten digits are used. I.e 0 - 9. Subtracting a number from base 10, 100, 1000. An easy way to calculate is just subtracting all digits of a digit from 9 and last digit by 10.

For an example, subtracting 56 from 100:

100 - 56 = (9 - 5) | (10 - 6) = 44

Let's check it using our conventional method, in units place it is 6 there. So carry from tens place, there also 0, so so take carry from hundred places, I.e in units place has value 10 so subtracting 6 from 10 we get 4 and now in tens place there is digit 9. Now subtract 5 from 9 we get 9 - 5 = 4. So our answer is 44. So lengthy using carry.

If we use the first method we have to do just only subtract 9 from all digits and last digit from 10. This is one of the powerful sutra "All From 9 And Last From 10" Of Vedic Mathematics. We also know that complement of 56 is 44. As if we add 56 with 44 we get 100.

Next, try for subtracting 65 from 10000:

10000 - 65 = 10000 - 0065 = 9935.