815 ÷ 7 = 116 R3
Let's divide 815 by 7.

Step 1:
7 goes into 8 1 times with a remainder of 1.
Write down 1 as next digit of of the result. 
Result so far: 1
Subtract 7 from 8 to get 1.
Bring next digit (1) of the dividend behind the 1 and repeat the process: 11 / 7

Step 2:
7 goes into 11 1 times with a remainder of 4.
Write down 1 as next digit of of the result. 
Result so far: 11
Subtract 7 from 11 to get 4.
Bring next digit (5) of the dividend behind the 4 and repeat the process: 45 / 7

Step 3:
7 goes into 45 6 times with a remainder of 3.
Write down 6 as next digit of of the result. 
Result so far: 116
Subtract 42 from 45 to get 3.

The final result is 116 with a remainder of 3.