7781 ÷ 8 = 972 R5
Let's divide 7781 by 8.

Step 1:
8 goes into 7 0 times with a remainder of 7.
Write down 0 as next digit of of the result. 
Result so far: 0
Subtract 0 from 7 to get 7.
Bring next digit (7) of the dividend behind the 7 and repeat the process: 77 / 8

Step 2:
8 goes into 77 9 times with a remainder of 5.
Write down 9 as next digit of of the result. 
Result so far: 9
Subtract 72 from 77 to get 5.
Bring next digit (8) of the dividend behind the 5 and repeat the process: 58 / 8

Step 3:
8 goes into 58 7 times with a remainder of 2.
Write down 7 as next digit of of the result. 
Result so far: 97
Subtract 56 from 58 to get 2.
Bring next digit (1) of the dividend behind the 2 and repeat the process: 21 / 8

Step 4:
8 goes into 21 2 times with a remainder of 5.
Write down 2 as next digit of of the result. 
Result so far: 972
Subtract 16 from 21 to get 5.

The final result is 972 with a remainder of 5.