We're dividing 745937 by 21 
The aim is to understand the frequency of 21 in 745937.

Advancing to step 1:
When dividing 7 by 21, we get 0 with 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 (4) from the dividend and append it to 7, then repeat: 74 / 21

Moving on to step 2:
74 divided by 21 is 3 with a remainder of 11.
Use 3 as the next digit of our solution. 
Result so far: 3.0
Subtracting 63 from 74 leaves us with 11.
Take the next digit (5) from the dividend and append it to 11, then repeat: 115 / 21

Let's proceed to step 3:
When dividing 115 by 21, we get 5 with a remainder of 10.
Put 5 as the next digit of the answer. 
Result so far: 35.0
Subtracting 105 from 115 leaves us with 10.
Fetch the next digit (9) from the dividend, attach it to 10 and continue: 109 / 21

Let's proceed to step 4:
109 divided by 21 is 5 with a remainder of 4.
Write down 5 as next digit of the result. 
Result so far: 355.0
Deduct 105 from 109 and we're left with 4.
Take the next digit (3) from the dividend and append it to 4, then repeat: 43 / 21

Moving on to step 5:
21 can be fit into 43 2 times, resulting in a remainder of 1.
Record the quotient 2 as the next digit in the result. 
Result so far: 3552.0
The remainder is 1 after subtracting 42 from 43.
Take the next digit (7) from the dividend and append it to 1, then repeat: 17 / 21

Moving on to step 6:
When dividing 17 by 21, we get 0 with a remainder of 17.
The number 0 becomes the next digit in our result. 
Result so far: 35520.0
Deduct 0 from 17 and we're left with 17.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Moving on to step 7:
If we divide 170 by 21, we get 8 and a remainder of 2.
Put 8 as the next digit of the answer. 
Result so far: 35520.8
If we take 168 away from 170, we end up with 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Going ahead to step 8:
20 divided by 21 is 0 with a remainder of 20.
The next digit of our result is 0. 
Result so far: 35520.8
Subtracting 0 from 20 leaves us 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.

On to step 9:
21 goes into 200 9 times with a remainder of 11.
The number 9 becomes the next digit in our result. 
Result so far: 35520.809
If we take 189 away from 200, we end up 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.

Going ahead to step 10:
The number 21 fits into 110 5 times, leaving a remainder of 5.
Record the quotient 5 as the next digit in the result. 
Result so far: 35520.8095
Subtracting 105 from 110 leaves us 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.

Step 11:
The number 21 fits into 50 2 times, leaving a remainder of 8.
The next digit of our result is 2. 
Result so far: 35520.80952
The remainder is 8 after subtracting 42 from 50.
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 12:
The number 21 fits into 80 3 times, leaving a remainder of 17.
The next digit of our result is 3. 
Result so far: 35520.809523
Subtracting 63 from 80 leaves us with 17.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Advancing to step 13:
The number 21 fits into 170 8 times, leaving a remainder of 2.
Put 8 as the next digit of the answer. 
Result so far: 35520.8095238
Subtracting 168 from 170 leaves us with 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Moving on to step 14:
21 goes into 20 0 times with a remainder of 20.
Use 0 as the next digit of our solution. 
Result so far: 35520.8095238
If we subtract 0 from 20, we get 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

The quotient of the division is 35520.8095238, and the remainder is 2e-08.