21904 ÷ 2 = 10952 R0
Let's divide 21904 by 2.

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

Step 2:
2 goes into 1 0 times with a remainder of 1.
Write down 0 as next digit of of the result. 
Result so far: 10
Subtract 0 from 1 to get 1.
Bring next digit (9) of the dividend behind the 1 and repeat the process: 19 / 2

Step 3:
2 goes into 19 9 times with a remainder of 1.
Write down 9 as next digit of of the result. 
Result so far: 109
Subtract 18 from 19 to get 1.
Bring next digit (0) of the dividend behind the 1 and repeat the process: 10 / 2

Step 4:
2 goes into 10 5 times with a remainder of 0.
Write down 5 as next digit of of the result. 
Result so far: 1095
Subtract 10 from 10 to get 0.
Bring next digit (4) of the dividend behind the 0 and repeat the process: 4 / 2

Step 5:
2 goes into 4 2 times with a remainder of 0.
Write down 2 as next digit of of the result. 
Result so far: 10952
Subtract 4 from 4 to get 0.

The final result is 10952 with a remainder of 0.