We divide 581178 by 21
The aim is to understand the frequency of 21 in 581178.

Let's proceed to step 1:
5 divided by 21 is 0 with a remainder of 5.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtracting 0 from 5 leaves us with 5.
Append the next digit (8) from the dividend to 5 and continue with: 58 / 21

Moving on to step 2:
21 can be fit into 58 2 times, resulting in a remainder of 16.
Put 2 as the next digit of the answer. 
Result so far: 2.0
If we subtract 42 from 58, we get 16.
Grab the next digit (1) from the dividend, add it to 16, then carry on: 161 / 21

Let's proceed to step 3:
21 goes into 161 7 times with a remainder of 14.
Write down 7 as next digit of the result. 
Result so far: 27.0
Subtracting 147 from 161 leaves us with 14.
Take the next digit (1) from the dividend and append it to 14, then repeat: 141 / 21

Moving on to step 4:
The number 21 fits into 141 6 times, leaving a remainder of 15.
The next digit of our result is 6. 
Result so far: 276.0
If we subtract 126 from 141, we get 15.
Fetch the next digit (7) from the dividend, attach it to 15 and continue: 157 / 21

Moving on to step 5:
21 goes into 157 7 times with a remainder of 10.
Write down 7 as next digit of the result. 
Result so far: 2767.0
If we take 147 away from 157, we end up with 10.
Grab the next digit (8) from the dividend, add it to 10, then carry on: 108 / 21

Advancing to step 6:
When dividing 108 by 21, we get 5 with a remainder of 3.
Record the quotient 5 as the next digit in the result. 
Result so far: 27675.0
The remainder is 3 after subtracting 105 from 108.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Advancing to step 7:
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: 27675.1
Subtracting 21 from 30 leaves us 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.

Advancing to step 8:
21 goes into 90 4 times with a remainder of 6.
Write down 4 as next digit of the result. 
Result so far: 27675.14
Subtract 84 from 90 to get 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 9:
When dividing 60 by 21, we get 2 with a remainder of 18.
The number 2 becomes the next digit in our result. 
Result so far: 27675.142
Subtract 42 from 60 to 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.

Let's proceed to step 10:
If we divide 180 by 21, we get 8 and a remainder of 12.
Put 8 as the next digit of the answer. 
Result so far: 27675.1428
Deduct 168 from 180 and we're left 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 11:
The number 21 fits into 120 5 times, leaving a remainder of 15.
Write down 5 as next digit of the result. 
Result so far: 27675.14285
Subtract 105 from 120 to get 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Let's proceed to step 12:
21 goes into 150 7 times with a remainder of 3.
Write down 7 as next digit of the result. 
Result so far: 27675.142857
If we take 147 away from 150, we end up 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 13:
If we divide 30 by 21, we get 1 and a remainder of 9.
Put 1 as the next digit of the answer. 
Result so far: 27675.1428571
Subtract 21 from 30 to get 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

On to step 14:
If we divide 90 by 21, we get 4 and a remainder of 6.
Write down 4 as next digit of the result. 
Result so far: 27675.14285714
Deduct 84 from 90 and we're left 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.

The final outcome is 27675.14285714, with a leftover of 6e-09.