21854 ÷ 3 = 7284 R2
Let's divide 21854 by 3.

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 (8) of the dividend behind the 0 and repeat the process: 8 / 3

Step 3:
3 goes into 8 2 times with a remainder of 2.
Write down 2 as next digit of of the result. 
Result so far: 72
Subtract 6 from 8 to get 2.
Bring next digit (5) of the dividend behind the 2 and repeat the process: 25 / 3

Step 4:
3 goes into 25 8 times with a remainder of 1.
Write down 8 as next digit of of the result. 
Result so far: 728
Subtract 24 from 25 to get 1.
Bring next digit (4) of the dividend behind the 1 and repeat the process: 14 / 3

Step 5:
3 goes into 14 4 times with a remainder of 2.
Write down 4 as next digit of of the result. 
Result so far: 7284
Subtract 12 from 14 to get 2.

The final result is 7284 with a remainder of 2.