We look at the division of 705915 by 21 
The aim is to understand the frequency of 21 in 705915.

Moving on to step 1:
21 can be fit into 7 0 times, resulting in a remainder of 7.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we take 0 away from 7, we end up with 7.
Fetch the next digit (0) from the dividend, attach it to 7 and continue: 70 / 21

Going ahead to step 2:
When dividing 70 by 21, we get 3 with a remainder of 7.
The next digit of our result is 3. 
Result so far: 3.0
If we take 63 away from 70, we end up with 7.
Take the next digit (5) from the dividend and append it to 7, then repeat: 75 / 21

Advancing to step 3:
The number 21 fits into 75 3 times, leaving a remainder of 12.
Write down 3 as next digit of the result. 
Result so far: 33.0
Subtract 63 from 75 to get 12.
Include the next digit (9) from the dividend after 12, then repeat: 129 / 21

Moving on to step 4:
129 divided by 21 is 6 with a remainder of 3.
Record the quotient 6 as the next digit in the result. 
Result so far: 336.0
If we take 126 away from 129, we end up with 3.
Append the next digit (1) from the dividend to 3 and continue with: 31 / 21

On to step 5:
21 can be fit into 31 1 times, resulting in a remainder of 10.
Write down 1 as next digit of the result. 
Result so far: 3361.0
If we subtract 21 from 31, we get 10.
Include the next digit (5) from the dividend after 10, then repeat: 105 / 21

Step 6:
21 can be fit into 105 5 times, resulting in a remainder of 0.
Record the quotient 5 as the next digit in the result. 
Result so far: 33615.0
The remainder is 0 after subtracting 105 from 105.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Moving on to step 7:
When dividing 0 by 21, we get 0 with a remainder of 0.
Record the quotient 0 as the next digit in the result. 
Result so far: 33615.0
Subtract 0 from 0 to get 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Advancing to step 8:
When dividing 0 by 21, we get 0 with a remainder of 0.
Put 0 as the next digit of the answer. 
Result so far: 33615.0
Subtract 0 from 0 to get 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

The final result is 33615.0 with a remainder of 0.0.