We're dividing 161232 by 21 
The aim is to understand the frequency of 21 in 161232.

Moving on to step 1:
21 can be fit into 1 0 times, resulting in a remainder of 1.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtracting 0 from 1 leaves us with 1.
Bring next digit (6) of the dividend behind the 1 and repeat the process: 16 / 21

Going ahead to step 2:
16 divided by 21 is 0 with a remainder of 16.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Deduct 0 from 16 and we're left with 16.
Fetch the next digit (1) from the dividend, attach it to 16 and continue: 161 / 21

Let's proceed to step 3:
161 divided by 21 is 7 with a remainder of 14.
The next digit of our result is 7. 
Result so far: 7.0
If we subtract 147 from 161, we get 14.
Append the next digit (2) from the dividend to 14 and continue with: 142 / 21

Moving on to step 4:
21 goes into 142 6 times with a remainder of 16.
Write down 6 as next digit of the result. 
Result so far: 76.0
Subtract 126 from 142 to get 16.
Grab the next digit (3) from the dividend, add it to 16, then carry on: 163 / 21

Moving on to step 5:
163 divided by 21 is 7 with a remainder of 16.
The number 7 becomes the next digit in our result. 
Result so far: 767.0
If we take 147 away from 163, we end up with 16.
Append the next digit (2) from the dividend to 16 and continue with: 162 / 21

Step 6:
If we divide 162 by 21, we get 7 and a remainder of 15.
Put 7 as the next digit of the answer. 
Result so far: 7677.0
Deduct 147 from 162 and we're left with 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Going ahead to step 7:
When dividing 150 by 21, we get 7 with a remainder of 3.
Record the quotient 7 as the next digit in the result. 
Result so far: 7677.7
Subtract 147 from 150 to get 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Going ahead to step 8:
21 can be fit into 30 1 times, resulting in a remainder of 9.
The number 1 becomes the next digit in our result. 
Result so far: 7677.71
Deduct 21 from 30 and we're left with 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Step 9:
The number 21 fits into 90 4 times, leaving a remainder of 6.
Put 4 as the next digit of the answer. 
Result so far: 7677.714
Subtracting 84 from 90 leaves us with 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Step 10:
21 goes into 60 2 times with a remainder of 18.
The number 2 becomes the next digit in our result. 
Result so far: 7677.7142
If we subtract 42 from 60, we get 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

Advancing to step 11:
21 can be fit into 180 8 times, resulting in a remainder of 12.
Record the quotient 8 as the next digit in the result. 
Result so far: 7677.71428
Subtracting 168 from 180 leaves us with 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Going ahead to step 12:
When dividing 120 by 21, we get 5 with a remainder of 15.
The next digit of our result is 5. 
Result so far: 7677.714285
The remainder is 15 after subtracting 105 from 120.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Advancing to step 13:
When dividing 150 by 21, we get 7 with a remainder of 3.
Record the quotient 7 as the next digit in the result. 
Result so far: 7677.7142857
Deduct 147 from 150 and we're left with 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Going ahead to step 14:
When dividing 30 by 21, we get 1 with a remainder of 9.
The number 1 becomes the next digit in our result. 
Result so far: 7677.71428571
If we take 21 away from 30, we end up with 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

The final outcome is 7677.71428571, with a leftover of 9e-09.