We're dividing 721497 by 51 
The aim is to understand the frequency of 51 in 721497.

Step 1:
7 divided by 51 is 0 with a remainder of 7.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtracting 0 from 7 leaves us with 7.
Take the next digit (2) from the dividend and append it to 7, then repeat: 72 / 51

Let's proceed to step 2:
51 goes into 72 1 times with a remainder of 21.
Use 1 as the next digit of our solution. 
Result so far: 1.0
Deduct 51 from 72 and we're left with 21.
Bring next digit (1) of the dividend behind the 21 and repeat the process: 211 / 51

Going ahead to step 3:
When dividing 211 by 51, we get 4 with a remainder of 7.
Put 4 as the next digit of the answer. 
Result so far: 14.0
Subtract 204 from 211 to get 7.
Include the next digit (4) from the dividend after 7, then repeat: 74 / 51

Advancing to step 4:
The number 51 fits into 74 1 times, leaving a remainder of 23.
Use 1 as the next digit of our solution. 
Result so far: 141.0
Subtract 51 from 74 to get 23.
Include the next digit (9) from the dividend after 23, then repeat: 239 / 51

Moving on to step 5:
51 goes into 239 4 times with a remainder of 35.
Record the quotient 4 as the next digit in the result. 
Result so far: 1414.0
Subtracting 204 from 239 leaves us with 35.
Take the next digit (7) from the dividend and append it to 35, then repeat: 357 / 51

Step 6:
If we divide 357 by 51, we get 7 and a remainder of 0.
Write down 7 as next digit of the result. 
Result so far: 14147.0
Subtracting 357 from 357 leaves us with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Moving on to step 7:
If we divide 0 by 51, we get 0 and a remainder of 0.
The number 0 becomes the next digit in our result. 
Result so far: 14147.0
If we take 0 away from 0, we end up with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Moving on to step 8:
0 divided by 51 is 0 with a remainder of 0.
Write down 0 as next digit of the result. 
Result so far: 14147.0
Deduct 0 from 0 and we're left with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

The final outcome is 14147.0, with a leftover of 0.0.