We look at the division of 402373 by 51 
The aim is to understand the frequency of 51 in 402373.

Moving on to step 1:
If we divide 4 by 51, we get 0 and a remainder of 4.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we take 0 away from 4, we end up with 4.
Include the next digit (0) from the dividend after 4, then repeat: 40 / 51

Advancing to step 2:
51 can be fit into 40 0 times, resulting in a remainder of 40.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtracting 0 from 40 leaves us with 40.
Grab the next digit (2) from the dividend, add it to 40, then carry on: 402 / 51

Moving on to step 3:
51 can be fit into 402 7 times, resulting in a remainder of 45.
The number 7 becomes the next digit in our result. 
Result so far: 7.0
The remainder is 45 after subtracting 357 from 402.
Append the next digit (3) from the dividend to 45 and continue with: 453 / 51

Advancing to step 4:
When dividing 453 by 51, we get 8 with a remainder of 45.
Write down 8 as next digit of the result. 
Result so far: 78.0
If we subtract 408 from 453, we get 45.
Grab the next digit (7) from the dividend, add it to 45, then carry on: 457 / 51

Let's proceed to step 5:
When dividing 457 by 51, we get 8 with a remainder of 49.
The number 8 becomes the next digit in our result. 
Result so far: 788.0
If we subtract 408 from 457, we get 49.
Grab the next digit (3) from the dividend, add it to 49, then carry on: 493 / 51

On to step 6:
51 can be fit into 493 9 times, resulting in a remainder of 34.
Put 9 as the next digit of the answer. 
Result so far: 7889.0
Subtracting 459 from 493 leaves us with 34.
Since there are no more digits in the dividend, we add a zero to the remainder making it 340, and continue the process.

Going ahead to step 7:
The number 51 fits into 340 6 times, leaving a remainder of 34.
Use 6 as the next digit of our solution. 
Result so far: 7889.6
If we subtract 306 from 340, we get 34.
Since there are no more digits in the dividend, we add a zero to the remainder making it 340, and continue the process.

On to step 8:
51 goes into 340 6 times with a remainder of 34.
The number 6 becomes the next digit in our result. 
Result so far: 7889.66
Subtracting 306 from 340 leaves us with 34.
Since there are no more digits in the dividend, we add a zero to the remainder making it 340, and continue the process.

The quotient of the division is 7889.66, and the remainder is 0.034.