99999 ÷ 1 = 99999 R0
We're going to perform division on 99999 with 1 as the divisor.

Step 1:
1 goes into 9 9 times with a remainder of 0.
Write down 9 as next digit of of the result. 
Result so far: 9
Subtract 9 from 9 to get 0.
Bring next digit (9) of the dividend behind the 0 and repeat the process: 9 / 1

Step 2:
1 goes into 9 9 times with a remainder of 0.
Write down 9 as next digit of of the result. 
Result so far: 99
Subtract 9 from 9 to get 0.
Bring next digit (9) of the dividend behind the 0 and repeat the process: 9 / 1

Step 3:
1 goes into 9 9 times with a remainder of 0.
Write down 9 as next digit of of the result. 
Result so far: 999
Subtract 9 from 9 to get 0.
Bring next digit (9) of the dividend behind the 0 and repeat the process: 9 / 1

Step 4:
1 goes into 9 9 times with a remainder of 0.
Write down 9 as next digit of of the result. 
Result so far: 9999
Subtract 9 from 9 to get 0.
Bring next digit (9) of the dividend behind the 0 and repeat the process: 9 / 1

Step 5:
1 goes into 9 9 times with a remainder of 0.
Write down 9 as next digit of of the result. 
Result so far: 99999
Subtract 9 from 9 to get 0.

The final result is 99999 with a remainder of 0.