We divide 13253671 by 399
The aim is to understand the frequency of 399 in 13253671.

On to step 1:
399 goes into 1 0 times with a remainder of 1.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 1 and we're left with 1.
Grab the next digit (3) from the dividend, add it to 1, then carry on: 13 / 399

Step 2:
If we divide 13 by 399, we get 0 and a remainder of 13.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtract 0 from 13 to get 13.
Include the next digit (2) from the dividend after 13, then repeat: 132 / 399

Going ahead to step 3:
132 divided by 399 is 0 with a remainder of 132.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we take 0 away from 132, we end up with 132.
Fetch the next digit (5) from the dividend, attach it to 132 and continue: 1325 / 399

Advancing to step 4:
399 can be fit into 1325 3 times, resulting in a remainder of 128.
Put 3 as the next digit of the answer. 
Result so far: 3.0
Subtracting 1197 from 1325 leaves us with 128.
Take the next digit (3) from the dividend and append it to 128, then repeat: 1283 / 399

Advancing to step 5:
1283 divided by 399 is 3 with a remainder of 86.
The next digit of our result is 3. 
Result so far: 33.0
Subtracting 1197 from 1283 leaves us with 86.
Fetch the next digit (6) from the dividend, attach it to 86 and continue: 866 / 399

Going ahead to step 6:
The number 399 fits into 866 2 times, leaving a remainder of 68.
Use 2 as the next digit of our solution. 
Result so far: 332.0
The remainder is 68 after subtracting 798 from 866.
Include the next digit (7) from the dividend after 68, then repeat: 687 / 399

Moving on to step 7:
If we divide 687 by 399, we get 1 and a remainder of 288.
Put 1 as the next digit of the answer. 
Result so far: 3321.0
Deduct 399 from 687 and we're left with 288.
Bring next digit (1) of the dividend behind the 288 and repeat the process: 2881 / 399

Step 8:
399 can be fit into 2881 7 times, resulting in a remainder of 88.
Record the quotient 7 as the next digit in the result. 
Result so far: 33217.0
Deduct 2793 from 2881 and we're left with 88.
Since there are no more digits in the dividend, we add a zero to the remainder making it 880, and continue the process.

Advancing to step 9:
When dividing 880 by 399, we get 2 with a remainder of 82.
Record the quotient 2 as the next digit in the result. 
Result so far: 33217.2
Deduct 798 from 880 and we're left with 82.
Since there are no more digits in the dividend, we add a zero to the remainder making it 820, and continue the process.

Moving on to step 10:
399 can be fit into 820 2 times, resulting in a remainder of 22.
Use 2 as the next digit of our solution. 
Result so far: 33217.22
The remainder is 22 after subtracting 798 from 820.
Since there are no more digits in the dividend, we add a zero to the remainder making it 220, and continue the process.

Our division results in 33217.22 with a remaining 0.022.