75218828 ÷ 420 
The aim is to understand the frequency of 420 in 75218828.

Going ahead to step 1:
If we divide 7 by 420, we get 0 and a remainder of 7.
The next digit of our result is 0. 
Result so far: 0.0
The remainder is 7 after subtracting 0 from 7.
Include the next digit (5) from the dividend after 7, then repeat: 75 / 420

Going ahead to step 2:
75 divided by 420 is 0 with a remainder of 75.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we subtract 0 from 75, we get 75.
Take the next digit (2) from the dividend and append it to 75, then repeat: 752 / 420

Step 3:
If we divide 752 by 420, we get 1 and a remainder of 332.
Write down 1 as next digit of the result. 
Result so far: 1.0
The remainder is 332 after subtracting 420 from 752.
Fetch the next digit (1) from the dividend, attach it to 332 and continue: 3321 / 420

Let's proceed to step 4:
The number 420 fits into 3321 7 times, leaving a remainder of 381.
Use 7 as the next digit of our solution. 
Result so far: 17.0
Deduct 2940 from 3321 and we're left with 381.
Grab the next digit (8) from the dividend, add it to 381, then carry on: 3818 / 420

On to step 5:
If we divide 3818 by 420, we get 9 and a remainder of 38.
The next digit of our result is 9. 
Result so far: 179.0
Deduct 3780 from 3818 and we're left with 38.
Include the next digit (8) from the dividend after 38, then repeat: 388 / 420

On to step 6:
420 can be fit into 388 0 times, resulting in a remainder of 388.
Record the quotient 0 as the next digit in the result. 
Result so far: 1790.0
Deduct 0 from 388 and we're left with 388.
Grab the next digit (2) from the dividend, add it to 388, then carry on: 3882 / 420

Let's proceed to step 7:
420 can be fit into 3882 9 times, resulting in a remainder of 102.
Use 9 as the next digit of our solution. 
Result so far: 17909.0
If we take 3780 away from 3882, we end up with 102.
Take the next digit (8) from the dividend and append it to 102, then repeat: 1028 / 420

Moving on to step 8:
The number 420 fits into 1028 2 times, leaving a remainder of 188.
Put 2 as the next digit of the answer. 
Result so far: 179092.0
Subtract 840 from 1028 to 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.

On to step 9:
If we divide 1880 by 420, we get 4 and a remainder of 200.
Use 4 as the next digit of our solution. 
Result so far: 179092.4
If we subtract 1680 from 1880, we get 200.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2000, and continue the process.

Moving on to step 10:
420 can be fit into 2000 4 times, resulting in a remainder of 320.
Write down 4 as next digit of the result. 
Result so far: 179092.44
If we take 1680 away from 2000, we end up with 320.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3200, and continue the process.

The quotient of the division is 179092.44, and the remainder is 0.32.