750629 divided by 21 
The aim is to understand the frequency of 21 in 750629.

On to step 1:
If we divide 7 by 21, we get 0 and a remainder of 7.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we subtract 0 from 7, we get 7.
Take the next digit (5) from the dividend and append it to 7, then repeat: 75 / 21

Step 2:
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: 3.0
If we take 63 away from 75, we end up with 12.
Take the next digit (0) from the dividend and append it to 12, then repeat: 120 / 21

Going ahead to step 3:
When dividing 120 by 21, we get 5 with a remainder of 15.
The number 5 becomes the next digit in our result. 
Result so far: 35.0
Deduct 105 from 120 and we're left with 15.
Grab the next digit (6) from the dividend, add it to 15, then carry on: 156 / 21

Let's proceed to step 4:
If we divide 156 by 21, we get 7 and a remainder of 9.
Record the quotient 7 as the next digit in the result. 
Result so far: 357.0
Subtract 147 from 156 to get 9.
Take the next digit (2) from the dividend and append it to 9, then repeat: 92 / 21

Moving on to step 5:
If we divide 92 by 21, we get 4 and a remainder of 8.
Write down 4 as next digit of the result. 
Result so far: 3574.0
Deduct 84 from 92 and we're left with 8.
Append the next digit (9) from the dividend to 8 and continue with: 89 / 21

Going ahead to step 6:
When dividing 89 by 21, we get 4 with a remainder of 5.
Write down 4 as next digit of the result. 
Result so far: 35744.0
The remainder is 5 after subtracting 84 from 89.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Step 7:
21 can be fit into 50 2 times, resulting in a remainder of 8.
Record the quotient 2 as the next digit in the result. 
Result so far: 35744.2
Subtracting 42 from 50 leaves us with 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Going ahead to step 8:
The number 21 fits into 80 3 times, leaving a remainder of 17.
Put 3 as the next digit of the answer. 
Result so far: 35744.23
Subtract 63 from 80 to get 17.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Let's proceed to step 9:
21 can be fit into 170 8 times, resulting in a remainder of 2.
Put 8 as the next digit of the answer. 
Result so far: 35744.238
If we subtract 168 from 170, we get 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Advancing to step 10:
The number 21 fits into 20 0 times, leaving a remainder of 20.
Use 0 as the next digit of our solution. 
Result so far: 35744.238
Deduct 0 from 20 and we're left with 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Advancing to step 11:
21 goes into 200 9 times with a remainder of 11.
The next digit of our result is 9. 
Result so far: 35744.23809
Deduct 189 from 200 and we're left with 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Step 12:
110 divided by 21 is 5 with a remainder of 5.
Use 5 as the next digit of our solution. 
Result so far: 35744.238095
Deduct 105 from 110 and we're left with 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Let's proceed to step 13:
21 goes into 50 2 times with a remainder of 8.
Put 2 as the next digit of the answer. 
Result so far: 35744.2380952
Subtract 42 from 50 to get 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Step 14:
21 can be fit into 80 3 times, resulting in a remainder of 17.
Put 3 as the next digit of the answer. 
Result so far: 35744.23809523
The remainder is 17 after subtracting 63 from 80.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

After the division, we end up with 35744.23809523 and a remainder of 1.7e-08.