87891658 divided by 391 
The aim is to understand the frequency of 391 in 87891658.

Advancing to step 1:
If we divide 8 by 391, we get 0 and a remainder of 8.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we subtract 0 from 8, we get 8.
Bring next digit (7) of the dividend behind the 8 and repeat the process: 87 / 391

Step 2:
If we divide 87 by 391, we get 0 and a remainder of 87.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we take 0 away from 87, we end up with 87.
Fetch the next digit (8) from the dividend, attach it to 87 and continue: 878 / 391

On to step 3:
391 can be fit into 878 2 times, resulting in a remainder of 96.
Write down 2 as next digit of the result. 
Result so far: 2.0
If we take 782 away from 878, we end up with 96.
Take the next digit (9) from the dividend and append it to 96, then repeat: 969 / 391

Going ahead to step 4:
391 can be fit into 969 2 times, resulting in a remainder of 187.
Write down 2 as next digit of the result. 
Result so far: 22.0
Subtract 782 from 969 to get 187.
Bring next digit (1) of the dividend behind the 187 and repeat the process: 1871 / 391

Advancing to step 5:
391 can be fit into 1871 4 times, resulting in a remainder of 307.
Put 4 as the next digit of the answer. 
Result so far: 224.0
The remainder is 307 after subtracting 1564 from 1871.
Bring next digit (6) of the dividend behind the 307 and repeat the process: 3076 / 391

Going ahead to step 6:
391 goes into 3076 7 times with a remainder of 339.
Record the quotient 7 as the next digit in the result. 
Result so far: 2247.0
The remainder is 339 after subtracting 2737 from 3076.
Grab the next digit (5) from the dividend, add it to 339, then carry on: 3395 / 391

Moving on to step 7:
The number 391 fits into 3395 8 times, leaving a remainder of 267.
Use 8 as the next digit of our solution. 
Result so far: 22478.0
Deduct 3128 from 3395 and we're left with 267.
Fetch the next digit (8) from the dividend, attach it to 267 and continue: 2678 / 391

On to step 8:
2678 divided by 391 is 6 with a remainder of 332.
Record the quotient 6 as the next digit in the result. 
Result so far: 224786.0
If we subtract 2346 from 2678, we 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.

Let's proceed to step 9:
If we divide 3320 by 391, we get 8 and a remainder of 192.
Put 8 as the next digit of the answer. 
Result so far: 224786.8
Subtract 3128 from 3320 to get 192.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1920, and continue the process.

Moving on to step 10:
1920 divided by 391 is 4 with a remainder of 356.
The next digit of our result is 4. 
Result so far: 224786.84
Subtract 1564 from 1920 to get 356.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3560, and continue the process.

Going ahead to step 11:
When dividing 3560 by 391, we get 9 with a remainder of 41.
Put 9 as the next digit of the answer. 
Result so far: 224786.849
Deduct 3519 from 3560 and we're left with 41.
Since there are no more digits in the dividend, we add a zero to the remainder making it 410, and continue the process.

Advancing to step 12:
410 divided by 391 is 1 with a remainder of 19.
Use 1 as the next digit of our solution. 
Result so far: 224786.8491
Subtracting 391 from 410 leaves us with 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Advancing to step 13:
The number 391 fits into 190 0 times, leaving a remainder of 190.
The number 0 becomes the next digit in our result. 
Result so far: 224786.8491
If we subtract 0 from 190, we get 190.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1900, and continue the process.

Moving on to step 14:
1900 divided by 391 is 4 with a remainder of 336.
Put 4 as the next digit of the answer. 
Result so far: 224786.849104
Deduct 1564 from 1900 and we're left with 336.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3360, and continue the process.

Moving on to step 15:
391 goes into 3360 8 times with a remainder of 232.
Put 8 as the next digit of the answer. 
Result so far: 224786.8491048
If we subtract 3128 from 3360, we get 232.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2320, and continue the process.

On to step 16:
When dividing 2320 by 391, we get 5 with a remainder of 365.
Write down 5 as next digit of the result. 
Result so far: 224786.84910485
If we subtract 1955 from 2320, we get 365.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3650, and continue the process.

After the division, we end up with 224786.84910485 and a remainder of 3.65e-07.