40043 ÷ 3 = 13347 R2
We're going to perform division on 40043 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 (0) of the dividend behind the 1 and repeat the process: 10 / 3

Step 3:
3 goes into 10 3 times with a remainder of 1.
Write down 3 as next digit of of the result. 
Result so far: 133
Subtract 9 from 10 to get 1.
Bring next digit (4) of the dividend behind the 1 and repeat the process: 14 / 3

Step 4:
3 goes into 14 4 times with a remainder of 2.
Write down 4 as next digit of of the result. 
Result so far: 1334
Subtract 12 from 14 to get 2.
Bring next digit (3) of the dividend behind the 2 and repeat the process: 23 / 3

Step 5:
3 goes into 23 7 times with a remainder of 2.
Write down 7 as next digit of of the result. 
Result so far: 13347
Subtract 21 from 23 to get 2.

The final result is 13347 with a remainder of 2.