We divide 752181 by 21
The aim is to understand the frequency of 21 in 752181.

On to step 1:
21 goes into 7 0 times with a remainder of 7.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we take 0 away from 7, 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 2:
The number 21 fits into 75 3 times, leaving a remainder of 12.
The number 3 becomes the next digit in our result. 
Result so far: 3.0
Subtract 63 from 75 to get 12.
Fetch the next digit (2) from the dividend, attach it to 12 and continue: 122 / 21

Let's proceed to step 3:
If we divide 122 by 21, we get 5 and a remainder of 17.
Use 5 as the next digit of our solution. 
Result so far: 35.0
The remainder is 17 after subtracting 105 from 122.
Bring next digit (1) of the dividend behind the 17 and repeat the process: 171 / 21

Advancing to step 4:
171 divided by 21 is 8 with a remainder of 3.
Write down 8 as next digit of the result. 
Result so far: 358.0
Deduct 168 from 171 and we're left with 3.
Append the next digit (8) from the dividend to 3 and continue with: 38 / 21

Moving on to step 5:
When dividing 38 by 21, we get 1 with a remainder of 17.
Use 1 as the next digit of our solution. 
Result so far: 3581.0
The remainder is 17 after subtracting 21 from 38.
Grab the next digit (1) from the dividend, add it to 17, then carry on: 171 / 21

On to step 6:
If we divide 171 by 21, we get 8 and a remainder of 3.
The next digit of our result is 8. 
Result so far: 35818.0
Subtracting 168 from 171 leaves us with 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Advancing to step 7:
If we divide 30 by 21, we get 1 and a remainder of 9.
The number 1 becomes the next digit in our result. 
Result so far: 35818.1
If we subtract 21 from 30, we get 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Advancing to step 8:
90 divided by 21 is 4 with a remainder of 6.
Put 4 as the next digit of the answer. 
Result so far: 35818.14
The remainder is 6 after subtracting 84 from 90.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Moving on to step 9:
21 can be fit into 60 2 times, resulting in a remainder of 18.
Use 2 as the next digit of our solution. 
Result so far: 35818.142
If we subtract 42 from 60, we get 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

Going ahead to step 10:
21 goes into 180 8 times with a remainder of 12.
Write down 8 as next digit of the result. 
Result so far: 35818.1428
Subtracting 168 from 180 leaves us with 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Going ahead to step 11:
When dividing 120 by 21, we get 5 with a remainder of 15.
Use 5 as the next digit of our solution. 
Result so far: 35818.14285
If we take 105 away from 120, we end up with 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Advancing to step 12:
21 can be fit into 150 7 times, resulting in a remainder of 3.
The next digit of our result is 7. 
Result so far: 35818.142857
Deduct 147 from 150 and we're left with 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

On to step 13:
If we divide 30 by 21, we get 1 and a remainder of 9.
Write down 1 as next digit of the result. 
Result so far: 35818.1428571
Deduct 21 from 30 and we're left with 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Let's proceed to step 14:
The number 21 fits into 90 4 times, leaving a remainder of 6.
The next digit of our result is 4. 
Result so far: 35818.14285714
Subtract 84 from 90 to get 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

After the division, we end up with 35818.14285714 and a remainder of 6e-09.