40155 ÷ 3 = 13385 R0
We're going to perform division on 40155 with 3 as the divisor.

Step 1:
3 goes into 4 1 times with a remainder of 1.
Write down 1 as next digit of of the result. 
Result so far: 1
Subtract 3 from 4 to get 1.
Bring next digit (0) of the dividend behind the 1 and repeat the process: 10 / 3

Step 2:
3 goes into 10 3 times with a remainder of 1.
Write down 3 as next digit of of the result. 
Result so far: 13
Subtract 9 from 10 to get 1.
Bring next digit (1) of the dividend behind the 1 and repeat the process: 11 / 3

Step 3:
3 goes into 11 3 times with a remainder of 2.
Write down 3 as next digit of of the result. 
Result so far: 133
Subtract 9 from 11 to get 2.
Bring next digit (5) of the dividend behind the 2 and repeat the process: 25 / 3

Step 4:
3 goes into 25 8 times with a remainder of 1.
Write down 8 as next digit of of the result. 
Result so far: 1338
Subtract 24 from 25 to get 1.
Bring next digit (5) of the dividend behind the 1 and repeat the process: 15 / 3

Step 5:
3 goes into 15 5 times with a remainder of 0.
Write down 5 as next digit of of the result. 
Result so far: 13385
Subtract 15 from 15 to get 0.

The final result is 13385 with a remainder of 0.