21313 ÷ 3 = 7104 R1
We're going to perform division on 21313 with 3 as the divisor.

Step 1:
3 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 / 3

Step 2:
3 goes into 21 7 times with a remainder of 0.
Write down 7 as next digit of of the result. 
Result so far: 7
Subtract 21 from 21 to get 0.
Bring next digit (3) of the dividend behind the 0 and repeat the process: 3 / 3

Step 3:
3 goes into 3 1 times with a remainder of 0.
Write down 1 as next digit of of the result. 
Result so far: 71
Subtract 3 from 3 to get 0.
Bring next digit (1) of the dividend behind the 0 and repeat the process: 1 / 3

Step 4:
3 goes into 1 0 times with a remainder of 1.
Write down 0 as next digit of of the result. 
Result so far: 710
Subtract 0 from 1 to get 1.
Bring next digit (3) of the dividend behind the 1 and repeat the process: 13 / 3

Step 5:
3 goes into 13 4 times with a remainder of 1.
Write down 4 as next digit of of the result. 
Result so far: 7104
Subtract 12 from 13 to get 1.

The final result is 7104 with a remainder of 1.