688510 ÷ 28 
The aim is to understand the frequency of 28 in 688510.

Moving on to step 1:
28 goes into 6 0 times with a remainder of 6.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we take 0 away from 6, we end up with 6.
Take the next digit (8) from the dividend and append it to 6, then repeat: 68 / 28

Let's proceed to step 2:
When dividing 68 by 28, we get 2 with a remainder of 12.
Use 2 as the next digit of our solution. 
Result so far: 2.0
Deduct 56 from 68 and we're left with 12.
Bring next digit (8) of the dividend behind the 12 and repeat the process: 128 / 28

Step 3:
The number 28 fits into 128 4 times, leaving a remainder of 16.
Record the quotient 4 as the next digit in the result. 
Result so far: 24.0
The remainder is 16 after subtracting 112 from 128.
Bring next digit (5) of the dividend behind the 16 and repeat the process: 165 / 28

On to step 4:
28 goes into 165 5 times with a remainder of 25.
Record the quotient 5 as the next digit in the result. 
Result so far: 245.0
Subtract 140 from 165 to get 25.
Bring next digit (1) of the dividend behind the 25 and repeat the process: 251 / 28

Step 5:
When dividing 251 by 28, we get 8 with a remainder of 27.
The next digit of our result is 8. 
Result so far: 2458.0
Deduct 224 from 251 and we're left with 27.
Append the next digit (0) from the dividend to 27 and continue with: 270 / 28

Advancing to step 6:
270 divided by 28 is 9 with a remainder of 18.
Use 9 as the next digit of our solution. 
Result so far: 24589.0
Subtract 252 from 270 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.

Advancing to step 7:
The number 28 fits into 180 6 times, leaving a remainder of 12.
The number 6 becomes the next digit in our result. 
Result so far: 24589.6
If we take 168 away from 180, we end up 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.

Step 8:
28 goes into 120 4 times with a remainder of 8.
Write down 4 as next digit of the result. 
Result so far: 24589.64
The remainder is 8 after subtracting 112 from 120.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Going ahead to step 9:
When dividing 80 by 28, we get 2 with a remainder of 24.
Record the quotient 2 as the next digit in the result. 
Result so far: 24589.642
If we take 56 away from 80, we end up 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 10:
28 can be fit into 240 8 times, resulting in a remainder of 16.
Use 8 as the next digit of our solution. 
Result so far: 24589.6428
If we subtract 224 from 240, we get 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

Step 11:
28 goes into 160 5 times with a remainder of 20.
The number 5 becomes the next digit in our result. 
Result so far: 24589.64285
If we take 140 away from 160, we end up with 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Let's proceed to step 12:
200 divided by 28 is 7 with a remainder of 4.
Put 7 as the next digit of the answer. 
Result so far: 24589.642857
Subtract 196 from 200 to get 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Going ahead to step 13:
40 divided by 28 is 1 with a remainder of 12.
Record the quotient 1 as the next digit in the result. 
Result so far: 24589.6428571
Subtract 28 from 40 to get 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 14:
120 divided by 28 is 4 with a remainder of 8.
Write down 4 as next digit of the result. 
Result so far: 24589.64285714
Deduct 112 from 120 and we're left with 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

The final outcome is 24589.64285714, with a leftover of 8e-09.