80435 ÷ 8 = 10054 R3
Let's divide 80435 by 8.

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

Step 2:
8 goes into 0 0 times with a remainder of 0.
Write down 0 as next digit of of the result. 
Result so far: 10
Subtract 0 from 0 to get 0.
Bring next digit (4) of the dividend behind the 0 and repeat the process: 4 / 8

Step 3:
8 goes into 4 0 times with a remainder of 4.
Write down 0 as next digit of of the result. 
Result so far: 100
Subtract 0 from 4 to get 4.
Bring next digit (3) of the dividend behind the 4 and repeat the process: 43 / 8

Step 4:
8 goes into 43 5 times with a remainder of 3.
Write down 5 as next digit of of the result. 
Result so far: 1005
Subtract 40 from 43 to get 3.
Bring next digit (5) of the dividend behind the 3 and repeat the process: 35 / 8

Step 5:
8 goes into 35 4 times with a remainder of 3.
Write down 4 as next digit of of the result. 
Result so far: 10054
Subtract 32 from 35 to get 3.

The final result is 10054 with a remainder of 3.