We're dividing 425991 by 84 
The aim is to understand the frequency of 84 in 425991.

On to step 1:
When dividing 4 by 84, we get 0 with a remainder of 4.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we subtract 0 from 4, we get 4.
Take the next digit (2) from the dividend and append it to 4, then repeat: 42 / 84

Going ahead to step 2:
If we divide 42 by 84, we get 0 and a remainder of 42.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we subtract 0 from 42, we get 42.
Append the next digit (5) from the dividend to 42 and continue with: 425 / 84

Going ahead to step 3:
84 can be fit into 425 5 times, resulting in a remainder of 5.
The number 5 becomes the next digit in our result. 
Result so far: 5.0
If we take 420 away from 425, we end up with 5.
Bring next digit (9) of the dividend behind the 5 and repeat the process: 59 / 84

Let's proceed to step 4:
59 divided by 84 is 0 with a remainder of 59.
Record the quotient 0 as the next digit in the result. 
Result so far: 50.0
The remainder is 59 after subtracting 0 from 59.
Grab the next digit (9) from the dividend, add it to 59, then carry on: 599 / 84

Going ahead to step 5:
84 goes into 599 7 times with a remainder of 11.
The next digit of our result is 7. 
Result so far: 507.0
Deduct 588 from 599 and we're left with 11.
Include the next digit (1) from the dividend after 11, then repeat: 111 / 84

Advancing to step 6:
84 goes into 111 1 times with a remainder of 27.
Record the quotient 1 as the next digit in the result. 
Result so far: 5071.0
Subtracting 84 from 111 leaves us with 27.
Since there are no more digits in the dividend, we add a zero to the remainder making it 270, and continue the process.

Going ahead to step 7:
84 can be fit into 270 3 times, resulting in a remainder of 18.
Put 3 as the next digit of the answer. 
Result so far: 5071.3
If we subtract 252 from 270, 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.

Let's proceed to step 8:
84 can be fit into 180 2 times, resulting in a remainder of 12.
Write down 2 as next digit of the result. 
Result so far: 5071.32
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.

Advancing to step 9:
120 divided by 84 is 1 with a remainder of 36.
Put 1 as the next digit of the answer. 
Result so far: 5071.321
The remainder is 36 after subtracting 84 from 120.
Since there are no more digits in the dividend, we add a zero to the remainder making it 360, and continue the process.

Let's proceed to step 10:
The number 84 fits into 360 4 times, leaving a remainder of 24.
Write down 4 as next digit of the result. 
Result so far: 5071.3214
Subtracting 336 from 360 leaves us with 24.
Since there are no more digits in the dividend, we add a zero to the remainder making it 240, and continue the process.

Advancing to step 11:
84 goes into 240 2 times with a remainder of 72.
Put 2 as the next digit of the answer. 
Result so far: 5071.32142
If we subtract 168 from 240, we get 72.
Since there are no more digits in the dividend, we add a zero to the remainder making it 720, and continue the process.

Going ahead to step 12:
When dividing 720 by 84, we get 8 with a remainder of 48.
The next digit of our result is 8. 
Result so far: 5071.321428
The remainder is 48 after subtracting 672 from 720.
Since there are no more digits in the dividend, we add a zero to the remainder making it 480, and continue the process.

Advancing to step 13:
The number 84 fits into 480 5 times, leaving a remainder of 60.
The number 5 becomes the next digit in our result. 
Result so far: 5071.3214285
Subtract 420 from 480 to get 60.
Since there are no more digits in the dividend, we add a zero to the remainder making it 600, and continue the process.

Moving on to step 14:
When dividing 600 by 84, we get 7 with a remainder of 12.
Use 7 as the next digit of our solution. 
Result so far: 5071.32142857
Deduct 588 from 600 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.

After the division, we end up with 5071.32142857 and a remainder of 1.2e-08.