We're dividing 663599 by 84 
The aim is to understand the frequency of 84 in 663599.

Step 1:
The number 84 fits into 6 0 times, leaving a remainder of 6.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we take 0 away from 6, we end up with 6.
Append the next digit (6) from the dividend to 6 and continue with: 66 / 84

On to step 2:
The number 84 fits into 66 0 times, leaving a remainder of 66.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 66 and we're left with 66.
Include the next digit (3) from the dividend after 66, then repeat: 663 / 84

Advancing to step 3:
The number 84 fits into 663 7 times, leaving a remainder of 75.
The number 7 becomes the next digit in our result. 
Result so far: 7.0
If we subtract 588 from 663, we get 75.
Fetch the next digit (5) from the dividend, attach it to 75 and continue: 755 / 84

Let's proceed to step 4:
755 divided by 84 is 8 with a remainder of 83.
Put 8 as the next digit of the answer. 
Result so far: 78.0
Subtracting 672 from 755 leaves us with 83.
Grab the next digit (9) from the dividend, add it to 83, then carry on: 839 / 84

Advancing to step 5:
The number 84 fits into 839 9 times, leaving a remainder of 83.
Record the quotient 9 as the next digit in the result. 
Result so far: 789.0
Subtract 756 from 839 to get 83.
Bring next digit (9) of the dividend behind the 83 and repeat the process: 839 / 84

Moving on to step 6:
84 can be fit into 839 9 times, resulting in a remainder of 83.
The number 9 becomes the next digit in our result. 
Result so far: 7899.0
The remainder is 83 after subtracting 756 from 839.
Since there are no more digits in the dividend, we add a zero to the remainder making it 830, and continue the process.

On to step 7:
When dividing 830 by 84, we get 9 with a remainder of 74.
Put 9 as the next digit of the answer. 
Result so far: 7899.9
Deduct 756 from 830 and we're left with 74.
Since there are no more digits in the dividend, we add a zero to the remainder making it 740, and continue the process.

Step 8:
740 divided by 84 is 8 with a remainder of 68.
Put 8 as the next digit of the answer. 
Result so far: 7899.98
If we take 672 away from 740, we end up with 68.
Since there are no more digits in the dividend, we add a zero to the remainder making it 680, and continue the process.

Step 9:
The number 84 fits into 680 8 times, leaving a remainder of 8.
Put 8 as the next digit of the answer. 
Result so far: 7899.988
If we subtract 672 from 680, we get 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

In conclusion, the division gives 7899.988 with a balance of 0.0008.