21008 ÷ 7 = 3001 R1
Let's divide 21008 by 7.

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 (0) of the dividend behind the 0 and repeat the process: 0 / 7

Step 3:
7 goes into 0 0 times with a remainder of 0.
Write down 0 as next digit of of the result. 
Result so far: 30
Subtract 0 from 0 to get 0.
Bring next digit (0) of the dividend behind the 0 and repeat the process: 0 / 7

Step 4:
7 goes into 0 0 times with a remainder of 0.
Write down 0 as next digit of of the result. 
Result so far: 300
Subtract 0 from 0 to get 0.
Bring next digit (8) of the dividend behind the 0 and repeat the process: 8 / 7

Step 5:
7 goes into 8 1 times with a remainder of 1.
Write down 1 as next digit of of the result. 
Result so far: 3001
Subtract 7 from 8 to get 1.

The final result is 3001 with a remainder of 1.