66691 ÷ 8 = 8336 R3
Alright, let's work through the division of 66691 by 8 step by step.

Step 1:
8 goes into 6 0 times with a remainder of 6.
Write down 0 as next digit of of the result. 
Result so far: 0
Subtract 0 from 6 to get 6.
Bring next digit (6) of the dividend behind the 6 and repeat the process: 66 / 8

Step 2:
8 goes into 66 8 times with a remainder of 2.
Write down 8 as next digit of of the result. 
Result so far: 8
Subtract 64 from 66 to get 2.
Bring next digit (6) of the dividend behind the 2 and repeat the process: 26 / 8

Step 3:
8 goes into 26 3 times with a remainder of 2.
Write down 3 as next digit of of the result. 
Result so far: 83
Subtract 24 from 26 to get 2.
Bring next digit (9) of the dividend behind the 2 and repeat the process: 29 / 8

Step 4:
8 goes into 29 3 times with a remainder of 5.
Write down 3 as next digit of of the result. 
Result so far: 833
Subtract 24 from 29 to get 5.
Bring next digit (1) of the dividend behind the 5 and repeat the process: 51 / 8

Step 5:
8 goes into 51 6 times with a remainder of 3.
Write down 6 as next digit of of the result. 
Result so far: 8336
Subtract 48 from 51 to get 3.

The final result is 8336 with a remainder of 3.