51615 ÷ 8 = 6451 R7
No problem, we've got 51615 and 8 for the division.

Step 1:
8 goes into 5 0 times with a remainder of 5.
Write down 0 as next digit of of the result. 
Result so far: 0
Subtract 0 from 5 to get 5.
Bring next digit (1) of the dividend behind the 5 and repeat the process: 51 / 8

Step 2:
8 goes into 51 6 times with a remainder of 3.
Write down 6 as next digit of of the result. 
Result so far: 6
Subtract 48 from 51 to get 3.
Bring next digit (6) of the dividend behind the 3 and repeat the process: 36 / 8

Step 3:
8 goes into 36 4 times with a remainder of 4.
Write down 4 as next digit of of the result. 
Result so far: 64
Subtract 32 from 36 to get 4.
Bring next digit (1) of the dividend behind the 4 and repeat the process: 41 / 8

Step 4:
8 goes into 41 5 times with a remainder of 1.
Write down 5 as next digit of of the result. 
Result so far: 645
Subtract 40 from 41 to get 1.
Bring next digit (5) of the dividend behind the 1 and repeat the process: 15 / 8

Step 5:
8 goes into 15 1 times with a remainder of 7.
Write down 1 as next digit of of the result. 
Result so far: 6451
Subtract 8 from 15 to get 7.

The final result is 6451 with a remainder of 7.