51878435 ÷ 221 
The aim is to understand the frequency of 221 in 51878435.

Let's proceed to step 1:
221 can be fit into 5 0 times, resulting in a remainder of 5.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
The remainder is 5 after subtracting 0 from 5.
Grab the next digit (1) from the dividend, add it to 5, then carry on: 51 / 221

Step 2:
51 divided by 221 is 0 with a remainder of 51.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtracting 0 from 51 leaves us with 51.
Bring next digit (8) of the dividend behind the 51 and repeat the process: 518 / 221

Let's proceed to step 3:
The number 221 fits into 518 2 times, leaving a remainder of 76.
Use 2 as the next digit of our solution. 
Result so far: 2.0
If we take 442 away from 518, we end up with 76.
Append the next digit (7) from the dividend to 76 and continue with: 767 / 221

Let's proceed to step 4:
The number 221 fits into 767 3 times, leaving a remainder of 104.
The next digit of our result is 3. 
Result so far: 23.0
Deduct 663 from 767 and we're left with 104.
Fetch the next digit (8) from the dividend, attach it to 104 and continue: 1048 / 221

On to step 5:
The number 221 fits into 1048 4 times, leaving a remainder of 164.
The next digit of our result is 4. 
Result so far: 234.0
Subtracting 884 from 1048 leaves us with 164.
Fetch the next digit (4) from the dividend, attach it to 164 and continue: 1644 / 221

On to step 6:
221 can be fit into 1644 7 times, resulting in a remainder of 97.
The next digit of our result is 7. 
Result so far: 2347.0
Subtracting 1547 from 1644 leaves us with 97.
Fetch the next digit (3) from the dividend, attach it to 97 and continue: 973 / 221

On to step 7:
The number 221 fits into 973 4 times, leaving a remainder of 89.
Write down 4 as next digit of the result. 
Result so far: 23474.0
If we take 884 away from 973, we end up with 89.
Bring next digit (5) of the dividend behind the 89 and repeat the process: 895 / 221

On to step 8:
895 divided by 221 is 4 with a remainder of 11.
Record the quotient 4 as the next digit in the result. 
Result so far: 234744.0
If we take 884 away from 895, we end up with 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Advancing to step 9:
221 goes into 110 0 times with a remainder of 110.
Write down 0 as next digit of the result. 
Result so far: 234744.0
If we take 0 away from 110, we end up with 110.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1100, and continue the process.

Moving on to step 10:
221 goes into 1100 4 times with a remainder of 216.
The number 4 becomes the next digit in our result. 
Result so far: 234744.04
The remainder is 216 after subtracting 884 from 1100.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2160, and continue the process.

On to step 11:
2160 divided by 221 is 9 with a remainder of 171.
The next digit of our result is 9. 
Result so far: 234744.049
Subtracting 1989 from 2160 leaves us with 171.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1710, and continue the process.

Advancing to step 12:
221 can be fit into 1710 7 times, resulting in a remainder of 163.
Put 7 as the next digit of the answer. 
Result so far: 234744.0497
If we subtract 1547 from 1710, we get 163.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1630, and continue the process.

Moving on to step 13:
221 goes into 1630 7 times with a remainder of 83.
The number 7 becomes the next digit in our result. 
Result so far: 234744.04977
Subtract 1547 from 1630 to get 83.
Since there are no more digits in the dividend, we add a zero to the remainder making it 830, and continue the process.

In conclusion, the division gives 234744.04977 with a balance of 8.3e-05.