21870 ÷ 5 = 4374 R0
We're going to perform division on 21870 with 5 as the divisor.

Step 1:
5 goes into 2 0 times with a remainder of 2.
Write down 0 as next digit of of the result. 
Result so far: 0
Subtract 0 from 2 to get 2.
Bring next digit (1) of the dividend behind the 2 and repeat the process: 21 / 5

Step 2:
5 goes into 21 4 times with a remainder of 1.
Write down 4 as next digit of of the result. 
Result so far: 4
Subtract 20 from 21 to get 1.
Bring next digit (8) of the dividend behind the 1 and repeat the process: 18 / 5

Step 3:
5 goes into 18 3 times with a remainder of 3.
Write down 3 as next digit of of the result. 
Result so far: 43
Subtract 15 from 18 to get 3.
Bring next digit (7) of the dividend behind the 3 and repeat the process: 37 / 5

Step 4:
5 goes into 37 7 times with a remainder of 2.
Write down 7 as next digit of of the result. 
Result so far: 437
Subtract 35 from 37 to get 2.
Bring next digit (0) of the dividend behind the 2 and repeat the process: 20 / 5

Step 5:
5 goes into 20 4 times with a remainder of 0.
Write down 4 as next digit of of the result. 
Result so far: 4374
Subtract 20 from 20 to get 0.

The final result is 4374 with a remainder of 0.