80399 ÷ 5 = 16079 R4
No problem, we've got 80399 and 5 for the division.

Step 1:
5 goes into 8 1 times with a remainder of 3.
Write down 1 as next digit of of the result. 
Result so far: 1
Subtract 5 from 8 to get 3.
Bring next digit (0) of the dividend behind the 3 and repeat the process: 30 / 5

Step 2:
5 goes into 30 6 times with a remainder of 0.
Write down 6 as next digit of of the result. 
Result so far: 16
Subtract 30 from 30 to get 0.
Bring next digit (3) of the dividend behind the 0 and repeat the process: 3 / 5

Step 3:
5 goes into 3 0 times with a remainder of 3.
Write down 0 as next digit of of the result. 
Result so far: 160
Subtract 0 from 3 to get 3.
Bring next digit (9) of the dividend behind the 3 and repeat the process: 39 / 5

Step 4:
5 goes into 39 7 times with a remainder of 4.
Write down 7 as next digit of of the result. 
Result so far: 1607
Subtract 35 from 39 to get 4.
Bring next digit (9) of the dividend behind the 4 and repeat the process: 49 / 5

Step 5:
5 goes into 49 9 times with a remainder of 4.
Write down 9 as next digit of of the result. 
Result so far: 16079
Subtract 45 from 49 to get 4.

The final result is 16079 with a remainder of 4.