21843 ÷ 7 = 3120 R3
We're going to perform division on 21843 with 7 as the divisor.

Step 1:
7 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 / 7

Step 2:
7 goes into 21 3 times with a remainder of 0.
Write down 3 as next digit of of the result. 
Result so far: 3
Subtract 21 from 21 to get 0.
Bring next digit (8) of the dividend behind the 0 and repeat the process: 8 / 7

Step 3:
7 goes into 8 1 times with a remainder of 1.
Write down 1 as next digit of of the result. 
Result so far: 31
Subtract 7 from 8 to get 1.
Bring next digit (4) of the dividend behind the 1 and repeat the process: 14 / 7

Step 4:
7 goes into 14 2 times with a remainder of 0.
Write down 2 as next digit of of the result. 
Result so far: 312
Subtract 14 from 14 to get 0.
Bring next digit (3) of the dividend behind the 0 and repeat the process: 3 / 7

Step 5:
7 goes into 3 0 times with a remainder of 3.
Write down 0 as next digit of of the result. 
Result so far: 3120
Subtract 0 from 3 to get 3.

The final result is 3120 with a remainder of 3.