We're dividing 802375 by 21 
The aim is to understand the frequency of 21 in 802375.

Advancing to step 1:
21 goes into 8 0 times with a remainder of 8.
The next digit of our result is 0. 
Result so far: 0.0
If we subtract 0 from 8, we get 8.
Fetch the next digit (0) from the dividend, attach it to 8 and continue: 80 / 21

Advancing to step 2:
If we divide 80 by 21, we get 3 and a remainder of 17.
Write down 3 as next digit of the result. 
Result so far: 3.0
Subtracting 63 from 80 leaves us with 17.
Bring next digit (2) of the dividend behind the 17 and repeat the process: 172 / 21

Advancing to step 3:
The number 21 fits into 172 8 times, leaving a remainder of 4.
Write down 8 as next digit of the result. 
Result so far: 38.0
Deduct 168 from 172 and we're left with 4.
Grab the next digit (3) from the dividend, add it to 4, then carry on: 43 / 21

Moving on to step 4:
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: 382.0
Deduct 42 from 43 and we're left with 1.
Bring next digit (7) of the dividend behind the 1 and repeat the process: 17 / 21

Going ahead to step 5:
If we divide 17 by 21, we get 0 and a remainder of 17.
The next digit of our result is 0. 
Result so far: 3820.0
Subtracting 0 from 17 leaves us with 17.
Include the next digit (5) from the dividend after 17, then repeat: 175 / 21

Moving on to step 6:
If we divide 175 by 21, we get 8 and a remainder of 7.
Record the quotient 8 as the next digit in the result. 
Result so far: 38208.0
Deduct 168 from 175 and we're left with 7.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

Going ahead to step 7:
21 goes into 70 3 times with a remainder of 7.
The number 3 becomes the next digit in our result. 
Result so far: 38208.3
Deduct 63 from 70 and we're left with 7.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

Let's proceed to step 8:
If we divide 70 by 21, we get 3 and a remainder of 7.
Write down 3 as next digit of the result. 
Result so far: 38208.33
Deduct 63 from 70 and we're left with 7.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

The quotient of the division is 38208.33, and the remainder is 0.007.