42003 ÷ 5 = 8400 R3
No problem, we've got 42003 and 5 for the division.

Step 1:
5 goes into 4 0 times with a remainder of 4.
Write down 0 as next digit of of the result. 
Result so far: 0
Subtract 0 from 4 to get 4.
Bring next digit (2) of the dividend behind the 4 and repeat the process: 42 / 5

Step 2:
5 goes into 42 8 times with a remainder of 2.
Write down 8 as next digit of of the result. 
Result so far: 8
Subtract 40 from 42 to get 2.
Bring next digit (0) of the dividend behind the 2 and repeat the process: 20 / 5

Step 3:
5 goes into 20 4 times with a remainder of 0.
Write down 4 as next digit of of the result. 
Result so far: 84
Subtract 20 from 20 to get 0.
Bring next digit (0) of the dividend behind the 0 and repeat the process: 0 / 5

Step 4:
5 goes into 0 0 times with a remainder of 0.
Write down 0 as next digit of of the result. 
Result so far: 840
Subtract 0 from 0 to get 0.
Bring next digit (3) of the dividend behind the 0 and repeat the process: 3 / 5

Step 5:
5 goes into 3 0 times with a remainder of 3.
Write down 0 as next digit of of the result. 
Result so far: 8400
Subtract 0 from 3 to get 3.

The final result is 8400 with a remainder of 3.