90381817 ÷ 391 
The aim is to understand the frequency of 391 in 90381817.

On to step 1:
The number 391 fits into 9 0 times, leaving a remainder of 9.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtract 0 from 9 to get 9.
Fetch the next digit (0) from the dividend, attach it to 9 and continue: 90 / 391

Step 2:
If we divide 90 by 391, we get 0 and a remainder of 90.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we subtract 0 from 90, we get 90.
Bring next digit (3) of the dividend behind the 90 and repeat the process: 903 / 391

Advancing to step 3:
903 divided by 391 is 2 with a remainder of 121.
Write down 2 as next digit of the result. 
Result so far: 2.0
If we subtract 782 from 903, we get 121.
Append the next digit (8) from the dividend to 121 and continue with: 1218 / 391

Going ahead to step 4:
391 can be fit into 1218 3 times, resulting in a remainder of 45.
The number 3 becomes the next digit in our result. 
Result so far: 23.0
Subtract 1173 from 1218 to get 45.
Take the next digit (1) from the dividend and append it to 45, then repeat: 451 / 391

Step 5:
The number 391 fits into 451 1 times, leaving a remainder of 60.
The number 1 becomes the next digit in our result. 
Result so far: 231.0
The remainder is 60 after subtracting 391 from 451.
Append the next digit (8) from the dividend to 60 and continue with: 608 / 391

Advancing to step 6:
391 goes into 608 1 times with a remainder of 217.
The number 1 becomes the next digit in our result. 
Result so far: 2311.0
Subtracting 391 from 608 leaves us with 217.
Fetch the next digit (1) from the dividend, attach it to 217 and continue: 2171 / 391

Advancing to step 7:
391 can be fit into 2171 5 times, resulting in a remainder of 216.
Record the quotient 5 as the next digit in the result. 
Result so far: 23115.0
If we subtract 1955 from 2171, we get 216.
Include the next digit (7) from the dividend after 216, then repeat: 2167 / 391

Let's proceed to step 8:
391 can be fit into 2167 5 times, resulting in a remainder of 212.
The next digit of our result is 5. 
Result so far: 231155.0
Subtracting 1955 from 2167 leaves us with 212.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2120, and continue the process.

Step 9:
When dividing 2120 by 391, we get 5 with a remainder of 165.
Put 5 as the next digit of the answer. 
Result so far: 231155.5
Subtracting 1955 from 2120 leaves us with 165.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1650, and continue the process.

Step 10:
If we divide 1650 by 391, we get 4 and a remainder of 86.
Use 4 as the next digit of our solution. 
Result so far: 231155.54
Deduct 1564 from 1650 and we're left with 86.
Since there are no more digits in the dividend, we add a zero to the remainder making it 860, and continue the process.

Advancing to step 11:
The number 391 fits into 860 2 times, leaving a remainder of 78.
Use 2 as the next digit of our solution. 
Result so far: 231155.542
The remainder is 78 after subtracting 782 from 860.
Since there are no more digits in the dividend, we add a zero to the remainder making it 780, and continue the process.

On to step 12:
780 divided by 391 is 1 with a remainder of 389.
The next digit of our result is 1. 
Result so far: 231155.5421
Subtract 391 from 780 to get 389.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3890, and continue the process.

On to step 13:
3890 divided by 391 is 9 with a remainder of 371.
Record the quotient 9 as the next digit in the result. 
Result so far: 231155.54219
If we subtract 3519 from 3890, we get 371.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3710, and continue the process.

Step 14:
391 goes into 3710 9 times with a remainder of 191.
The next digit of our result is 9. 
Result so far: 231155.542199
Subtract 3519 from 3710 to get 191.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1910, and continue the process.

In conclusion, the division gives 231155.542199 with a balance of 1.91e-05.