We look at the division of 42997654 by 521 
The aim is to understand the frequency of 521 in 42997654.

Advancing to step 1:
4 divided by 521 is 0 with a remainder of 4.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtracting 0 from 4 leaves us with 4.
Fetch the next digit (2) from the dividend, attach it to 4 and continue: 42 / 521

Going ahead to step 2:
The number 521 fits into 42 0 times, leaving a remainder of 42.
Put 0 as the next digit of the answer. 
Result so far: 0.0
The remainder is 42 after subtracting 0 from 42.
Include the next digit (9) from the dividend after 42, then repeat: 429 / 521

Step 3:
If we divide 429 by 521, we get 0 and a remainder of 429.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Deduct 0 from 429 and we're left with 429.
Include the next digit (9) from the dividend after 429, then repeat: 4299 / 521

Let's proceed to step 4:
521 goes into 4299 8 times with a remainder of 131.
Record the quotient 8 as the next digit in the result. 
Result so far: 8.0
If we take 4168 away from 4299, we end up with 131.
Append the next digit (7) from the dividend to 131 and continue with: 1317 / 521

Let's proceed to step 5:
If we divide 1317 by 521, we get 2 and a remainder of 275.
The number 2 becomes the next digit in our result. 
Result so far: 82.0
If we subtract 1042 from 1317, we get 275.
Grab the next digit (6) from the dividend, add it to 275, then carry on: 2756 / 521

Let's proceed to step 6:
The number 521 fits into 2756 5 times, leaving a remainder of 151.
The next digit of our result is 5. 
Result so far: 825.0
The remainder is 151 after subtracting 2605 from 2756.
Fetch the next digit (5) from the dividend, attach it to 151 and continue: 1515 / 521

Moving on to step 7:
521 can be fit into 1515 2 times, resulting in a remainder of 473.
Use 2 as the next digit of our solution. 
Result so far: 8252.0
Subtracting 1042 from 1515 leaves us with 473.
Fetch the next digit (4) from the dividend, attach it to 473 and continue: 4734 / 521

Going ahead to step 8:
The number 521 fits into 4734 9 times, leaving a remainder of 45.
Record the quotient 9 as the next digit in the result. 
Result so far: 82529.0
Subtracting 4689 from 4734 leaves us with 45.
Since there are no more digits in the dividend, we add a zero to the remainder making it 450, and continue the process.

Moving on to step 9:
521 can be fit into 450 0 times, resulting in a remainder of 450.
Use 0 as the next digit of our solution. 
Result so far: 82529.0
The remainder is 450 after subtracting 0 from 450.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4500, and continue the process.

On to step 10:
521 goes into 4500 8 times with a remainder of 332.
Use 8 as the next digit of our solution. 
Result so far: 82529.08
Subtract 4168 from 4500 to get 332.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3320, and continue the process.

Moving on to step 11:
If we divide 3320 by 521, we get 6 and a remainder of 194.
Use 6 as the next digit of our solution. 
Result so far: 82529.086
Deduct 3126 from 3320 and we're left with 194.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1940, and continue the process.

Moving on to step 12:
1940 divided by 521 is 3 with a remainder of 377.
The next digit of our result is 3. 
Result so far: 82529.0863
Subtract 1563 from 1940 to get 377.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3770, and continue the process.

Step 13:
The number 521 fits into 3770 7 times, leaving a remainder of 123.
Write down 7 as next digit of the result. 
Result so far: 82529.08637
If we take 3647 away from 3770, we end up with 123.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1230, and continue the process.

Let's proceed to step 14:
The number 521 fits into 1230 2 times, leaving a remainder of 188.
Record the quotient 2 as the next digit in the result. 
Result so far: 82529.086372
If we subtract 1042 from 1230, we get 188.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1880, and continue the process.

Moving on to step 15:
The number 521 fits into 1880 3 times, leaving a remainder of 317.
Put 3 as the next digit of the answer. 
Result so far: 82529.0863723
If we take 1563 away from 1880, we end up with 317.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3170, and continue the process.

Going ahead to step 16:
The number 521 fits into 3170 6 times, leaving a remainder of 44.
The number 6 becomes the next digit in our result. 
Result so far: 82529.08637236
The remainder is 44 after subtracting 3126 from 3170.
Since there are no more digits in the dividend, we add a zero to the remainder making it 440, and continue the process.

The quotient of the division is 82529.08637236, and the remainder is 4.4e-08.