We look at the division of 721687 by 89 
The aim is to understand the frequency of 89 in 721687.

Going ahead to step 1:
89 can be fit into 7 0 times, resulting in a remainder of 7.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we subtract 0 from 7, we get 7.
Grab the next digit (2) from the dividend, add it to 7, then carry on: 72 / 89

Step 2:
89 goes into 72 0 times with a remainder of 72.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we subtract 0 from 72, we get 72.
Grab the next digit (1) from the dividend, add it to 72, then carry on: 721 / 89

Let's proceed to step 3:
The number 89 fits into 721 8 times, leaving a remainder of 9.
The next digit of our result is 8. 
Result so far: 8.0
Subtracting 712 from 721 leaves us with 9.
Fetch the next digit (6) from the dividend, attach it to 9 and continue: 96 / 89

Let's proceed to step 4:
When dividing 96 by 89, we get 1 with a remainder of 7.
The next digit of our result is 1. 
Result so far: 81.0
The remainder is 7 after subtracting 89 from 96.
Include the next digit (8) from the dividend after 7, then repeat: 78 / 89

Let's proceed to step 5:
The number 89 fits into 78 0 times, leaving a remainder of 78.
Use 0 as the next digit of our solution. 
Result so far: 810.0
The remainder is 78 after subtracting 0 from 78.
Take the next digit (7) from the dividend and append it to 78, then repeat: 787 / 89

Moving on to step 6:
787 divided by 89 is 8 with a remainder of 75.
The number 8 becomes the next digit in our result. 
Result so far: 8108.0
Subtracting 712 from 787 leaves us with 75.
Since there are no more digits in the dividend, we add a zero to the remainder making it 750, and continue the process.

On to step 7:
89 can be fit into 750 8 times, resulting in a remainder of 38.
Record the quotient 8 as the next digit in the result. 
Result so far: 8108.8
If we subtract 712 from 750, we get 38.
Since there are no more digits in the dividend, we add a zero to the remainder making it 380, and continue the process.

On to step 8:
89 can be fit into 380 4 times, resulting in a remainder of 24.
Write down 4 as next digit of the result. 
Result so far: 8108.84
Subtract 356 from 380 to get 24.
Since there are no more digits in the dividend, we add a zero to the remainder making it 240, and continue the process.

Moving on to step 9:
If we divide 240 by 89, we get 2 and a remainder of 62.
Use 2 as the next digit of our solution. 
Result so far: 8108.842
If we subtract 178 from 240, we get 62.
Since there are no more digits in the dividend, we add a zero to the remainder making it 620, and continue the process.

On to step 10:
When dividing 620 by 89, we get 6 with a remainder of 86.
Put 6 as the next digit of the answer. 
Result so far: 8108.8426
If we take 534 away from 620, we end up with 86.
Since there are no more digits in the dividend, we add a zero to the remainder making it 860, and continue the process.

Going ahead to step 11:
89 can be fit into 860 9 times, resulting in a remainder of 59.
Put 9 as the next digit of the answer. 
Result so far: 8108.84269
The remainder is 59 after subtracting 801 from 860.
Since there are no more digits in the dividend, we add a zero to the remainder making it 590, and continue the process.

Advancing to step 12:
When dividing 590 by 89, we get 6 with a remainder of 56.
The number 6 becomes the next digit in our result. 
Result so far: 8108.842696
If we take 534 away from 590, we end up with 56.
Since there are no more digits in the dividend, we add a zero to the remainder making it 560, and continue the process.

Going ahead to step 13:
89 goes into 560 6 times with a remainder of 26.
Write down 6 as next digit of the result. 
Result so far: 8108.8426966
The remainder is 26 after subtracting 534 from 560.
Since there are no more digits in the dividend, we add a zero to the remainder making it 260, and continue the process.

After the division, we end up with 8108.8426966 and a remainder of 2.6e-07.