7654 - 3862 =
first write the problem like this, then solve from right to left
7654
- 3862
______
2 --------> solve 4 -2 = 2 , proceed to the next number
7654 --------> 6 is now 5, and 5 is now 15
- 3862
______
92 --------> next, solve 5 - 6 = cannot be because 6 is greater
than 5, so you need to borrow 1 from 6 making it
5, then put 1 to 5 to have 15, so 15 - 6 = 9
7554 --------> 7 is now 6, and 5 is now 15
- 3862
______
792 --------> next, solve 5 - 8 = cannot be because 8 is greater
than 5, so you need to borrow 1 from 7 making it
6, then put 1 to 5 to have 15, so 15 - 8 = 7
6554
- 3862
______
3792 --------> solve 6 - 3 = 3
And the answer is 3792
