51503 ÷ 8 = 6437 R7
Let's divide 51503 by 8.

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 (5) of the dividend behind the 3 and repeat the process: 35 / 8

Step 3:
8 goes into 35 4 times with a remainder of 3.
Write down 4 as next digit of of the result. 
Result so far: 64
Subtract 32 from 35 to get 3.
Bring next digit (0) of the dividend behind the 3 and repeat the process: 30 / 8

Step 4:
8 goes into 30 3 times with a remainder of 6.
Write down 3 as next digit of of the result. 
Result so far: 643
Subtract 24 from 30 to get 6.
Bring next digit (3) of the dividend behind the 6 and repeat the process: 63 / 8

Step 5:
8 goes into 63 7 times with a remainder of 7.
Write down 7 as next digit of of the result. 
Result so far: 6437
Subtract 56 from 63 to get 7.

The final result is 6437 with a remainder of 7.