We look at the division of 90520705 by 689 
The aim is to understand the frequency of 689 in 90520705.

Step 1:
When dividing 9 by 689, we get 0 with a remainder of 9.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtracting 0 from 9 leaves us with 9.
Append the next digit (0) from the dividend to 9 and continue with: 90 / 689

Step 2:
If we divide 90 by 689, we get 0 and a remainder of 90.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we subtract 0 from 90, we get 90.
Take the next digit (5) from the dividend and append it to 90, then repeat: 905 / 689

Let's proceed to step 3:
The number 689 fits into 905 1 times, leaving a remainder of 216.
The number 1 becomes the next digit in our result. 
Result so far: 1.0
The remainder is 216 after subtracting 689 from 905.
Include the next digit (2) from the dividend after 216, then repeat: 2162 / 689

Step 4:
If we divide 2162 by 689, we get 3 and a remainder of 95.
Record the quotient 3 as the next digit in the result. 
Result so far: 13.0
Subtracting 2067 from 2162 leaves us with 95.
Bring next digit (0) of the dividend behind the 95 and repeat the process: 950 / 689

Going ahead to step 5:
The number 689 fits into 950 1 times, leaving a remainder of 261.
Write down 1 as next digit of the result. 
Result so far: 131.0
Subtracting 689 from 950 leaves us with 261.
Fetch the next digit (7) from the dividend, attach it to 261 and continue: 2617 / 689

Advancing to step 6:
2617 divided by 689 is 3 with a remainder of 550.
Write down 3 as next digit of the result. 
Result so far: 1313.0
If we take 2067 away from 2617, we end up with 550.
Include the next digit (0) from the dividend after 550, then repeat: 5500 / 689

Going ahead to step 7:
If we divide 5500 by 689, we get 7 and a remainder of 677.
The number 7 becomes the next digit in our result. 
Result so far: 13137.0
If we take 4823 away from 5500, we end up with 677.
Bring next digit (5) of the dividend behind the 677 and repeat the process: 6775 / 689

Moving on to step 8:
The number 689 fits into 6775 9 times, leaving a remainder of 574.
Use 9 as the next digit of our solution. 
Result so far: 131379.0
If we take 6201 away from 6775, we end up with 574.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5740, and continue the process.

Advancing to step 9:
5740 divided by 689 is 8 with a remainder of 228.
Use 8 as the next digit of our solution. 
Result so far: 131379.8
If we subtract 5512 from 5740, we get 228.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2280, and continue the process.

On to step 10:
689 can be fit into 2280 3 times, resulting in a remainder of 213.
Use 3 as the next digit of our solution. 
Result so far: 131379.83
Subtracting 2067 from 2280 leaves us with 213.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2130, and continue the process.

Going ahead to step 11:
The number 689 fits into 2130 3 times, leaving a remainder of 63.
Write down 3 as next digit of the result. 
Result so far: 131379.833
If we subtract 2067 from 2130, we get 63.
Since there are no more digits in the dividend, we add a zero to the remainder making it 630, and continue the process.

The final outcome is 131379.833, with a leftover of 0.0063.