Let's divide 345475 by 21
The aim is to understand the frequency of 21 in 345475.

On to step 1:
3 divided by 21 is 0 with a remainder of 3.
The next digit of our result is 0. 
Result so far: 0.0
The remainder is 3 after subtracting 0 from 3.
Fetch the next digit (4) from the dividend, attach it to 3 and continue: 34 / 21

Step 2:
When dividing 34 by 21, we get 1 with a remainder of 13.
The number 1 becomes the next digit in our result. 
Result so far: 1.0
Subtract 21 from 34 to get 13.
Grab the next digit (5) from the dividend, add it to 13, then carry on: 135 / 21

Step 3:
135 divided by 21 is 6 with a remainder of 9.
The number 6 becomes the next digit in our result. 
Result so far: 16.0
Subtracting 126 from 135 leaves us with 9.
Fetch the next digit (4) from the dividend, attach it to 9 and continue: 94 / 21

Advancing to step 4:
21 can be fit into 94 4 times, resulting in a remainder of 10.
Put 4 as the next digit of the answer. 
Result so far: 164.0
If we take 84 away from 94, we end up with 10.
Take the next digit (7) from the dividend and append it to 10, then repeat: 107 / 21

Step 5:
107 divided by 21 is 5 with a remainder of 2.
Use 5 as the next digit of our solution. 
Result so far: 1645.0
If we take 105 away from 107, we end up with 2.
Append the next digit (5) from the dividend to 2 and continue with: 25 / 21

Advancing to step 6:
The number 21 fits into 25 1 times, leaving a remainder of 4.
Record the quotient 1 as the next digit in the result. 
Result so far: 16451.0
Subtract 21 from 25 to get 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Advancing to step 7:
The number 21 fits into 40 1 times, leaving a remainder of 19.
The next digit of our result is 1. 
Result so far: 16451.1
Subtracting 21 from 40 leaves us with 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

On to step 8:
21 goes into 190 9 times with a remainder of 1.
The number 9 becomes the next digit in our result. 
Result so far: 16451.19
If we subtract 189 from 190, we get 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Step 9:
If we divide 10 by 21, we get 0 and a remainder of 10.
The number 0 becomes the next digit in our result. 
Result so far: 16451.19
If we take 0 away from 10, we end up with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Advancing to step 10:
21 goes into 100 4 times with a remainder of 16.
Put 4 as the next digit of the answer. 
Result so far: 16451.1904
Subtracting 84 from 100 leaves us with 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

Going ahead to step 11:
When dividing 160 by 21, we get 7 with a remainder of 13.
Use 7 as the next digit of our solution. 
Result so far: 16451.19047
Subtracting 147 from 160 leaves us with 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

Advancing to step 12:
21 can be fit into 130 6 times, resulting in a remainder of 4.
Use 6 as the next digit of our solution. 
Result so far: 16451.190476
The remainder is 4 after subtracting 126 from 130.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

On to step 13:
If we divide 40 by 21, we get 1 and a remainder of 19.
Use 1 as the next digit of our solution. 
Result so far: 16451.1904761
Subtracting 21 from 40 leaves us with 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

On to step 14:
21 can be fit into 190 9 times, resulting in a remainder of 1.
Use 9 as the next digit of our solution. 
Result so far: 16451.19047619
Subtract 189 from 190 to get 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Our division results in 16451.19047619 with a remaining 1e-09.