Answer :

tmacar
538
-247
-------
291

8-7=1
you cant do 3-4 so you borrow 10 numbers from 5 and got 13-4=9
4-2=2
For this case we have the following operation:
 538 - 247
 To subtract both numbers we must follow the following steps:
 1) Subtraction is done from left to right:
 2) We subtract the first digits:
 8 - 7 = 1
 3) We subtract the second digits:
 3 - 4
 Since 4 is greater than 3 then we add a digit to 3 and accumulate it for the next subtraction:
 13 - 4 = 9
 4) We subtract the digit accumulated in the previous subtraction to the following number:
 5 - 2 - 1 = 2
 Finally the result is:
 538 - 247 = 291