972518 ÷ 21 
The aim is to understand the frequency of 21 in 972518.

Advancing to step 1:
The number 21 fits into 9 0 times, leaving a remainder of 9.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we subtract 0 from 9, we get 9.
Append the next digit (7) from the dividend to 9 and continue with: 97 / 21

Let's proceed to step 2:
21 can be fit into 97 4 times, resulting in a remainder of 13.
The number 4 becomes the next digit in our result. 
Result so far: 4.0
Subtract 84 from 97 to get 13.
Bring next digit (2) of the dividend behind the 13 and repeat the process: 132 / 21

Moving on to step 3:
21 can be fit into 132 6 times, resulting in a remainder of 6.
Use 6 as the next digit of our solution. 
Result so far: 46.0
If we take 126 away from 132, we end up with 6.
Grab the next digit (5) from the dividend, add it to 6, then carry on: 65 / 21

Moving on to step 4:
The number 21 fits into 65 3 times, leaving a remainder of 2.
Use 3 as the next digit of our solution. 
Result so far: 463.0
If we subtract 63 from 65, we get 2.
Append the next digit (1) from the dividend to 2 and continue with: 21 / 21

Step 5:
21 can be fit into 21 1 times, resulting in a remainder of 0.
Write down 1 as next digit of the result. 
Result so far: 4631.0
If we take 21 away from 21, we end up with 0.
Bring next digit (8) of the dividend behind the 0 and repeat the process: 8 / 21

Going ahead to step 6:
8 divided by 21 is 0 with a remainder of 8.
Use 0 as the next digit of our solution. 
Result so far: 46310.0
Deduct 0 from 8 and we're left 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.

Moving on to step 7:
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: 46310.3
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.

Moving on to step 8:
170 divided by 21 is 8 with a remainder of 2.
Write down 8 as next digit of the result. 
Result so far: 46310.38
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.

On to step 9:
The number 21 fits into 20 0 times, leaving a remainder of 20.
The number 0 becomes the next digit in our result. 
Result so far: 46310.38
If we take 0 away from 20, we end up 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 10:
200 divided by 21 is 9 with a remainder of 11.
The number 9 becomes the next digit in our result. 
Result so far: 46310.3809
If we subtract 189 from 200, we get 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

On to step 11:
21 can be fit into 110 5 times, resulting in a remainder of 5.
Put 5 as the next digit of the answer. 
Result so far: 46310.38095
The remainder is 5 after subtracting 105 from 110.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Step 12:
50 divided by 21 is 2 with a remainder of 8.
The number 2 becomes the next digit in our result. 
Result so far: 46310.380952
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.

Step 13:
21 can be fit into 80 3 times, resulting in a remainder of 17.
The next digit of our result is 3. 
Result so far: 46310.3809523
If we subtract 63 from 80, we 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 14:
21 can be fit into 170 8 times, resulting in a remainder of 2.
Write down 8 as next digit of the result. 
Result so far: 46310.38095238
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.

The quotient of the division is 46310.38095238, and the remainder is 2e-09.