64887700 divided by 399 
The aim is to understand the frequency of 399 in 64887700.

On to step 1:
399 goes into 6 0 times with a remainder of 6.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we take 0 away from 6, we end up with 6.
Include the next digit (4) from the dividend after 6, then repeat: 64 / 399

Going ahead to step 2:
If we divide 64 by 399, we get 0 and a remainder of 64.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtract 0 from 64 to get 64.
Bring next digit (8) of the dividend behind the 64 and repeat the process: 648 / 399

Advancing to step 3:
When dividing 648 by 399, we get 1 with a remainder of 249.
Record the quotient 1 as the next digit in the result. 
Result so far: 1.0
If we take 399 away from 648, we end up with 249.
Bring next digit (8) of the dividend behind the 249 and repeat the process: 2498 / 399

Step 4:
The number 399 fits into 2498 6 times, leaving a remainder of 104.
Use 6 as the next digit of our solution. 
Result so far: 16.0
If we subtract 2394 from 2498, we get 104.
Grab the next digit (7) from the dividend, add it to 104, then carry on: 1047 / 399

Going ahead to step 5:
The number 399 fits into 1047 2 times, leaving a remainder of 249.
Put 2 as the next digit of the answer. 
Result so far: 162.0
If we take 798 away from 1047, we end up with 249.
Bring next digit (7) of the dividend behind the 249 and repeat the process: 2497 / 399

Advancing to step 6:
If we divide 2497 by 399, we get 6 and a remainder of 103.
Put 6 as the next digit of the answer. 
Result so far: 1626.0
If we subtract 2394 from 2497, we get 103.
Grab the next digit (0) from the dividend, add it to 103, then carry on: 1030 / 399

Advancing to step 7:
399 can be fit into 1030 2 times, resulting in a remainder of 232.
Put 2 as the next digit of the answer. 
Result so far: 16262.0
If we take 798 away from 1030, we end up with 232.
Bring next digit (0) of the dividend behind the 232 and repeat the process: 2320 / 399

Step 8:
2320 divided by 399 is 5 with a remainder of 325.
The number 5 becomes the next digit in our result. 
Result so far: 162625.0
The remainder is 325 after subtracting 1995 from 2320.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3250, and continue the process.

On to step 9:
If we divide 3250 by 399, we get 8 and a remainder of 58.
Use 8 as the next digit of our solution. 
Result so far: 162625.8
If we take 3192 away from 3250, we end up with 58.
Since there are no more digits in the dividend, we add a zero to the remainder making it 580, and continue the process.

Step 10:
The number 399 fits into 580 1 times, leaving a remainder of 181.
Put 1 as the next digit of the answer. 
Result so far: 162625.81
The remainder is 181 after subtracting 399 from 580.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1810, and continue the process.

Let's proceed to step 11:
When dividing 1810 by 399, we get 4 with a remainder of 214.
Use 4 as the next digit of our solution. 
Result so far: 162625.814
If we take 1596 away from 1810, we end up with 214.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2140, and continue the process.

Moving on to step 12:
If we divide 2140 by 399, we get 5 and a remainder of 145.
Write down 5 as next digit of the result. 
Result so far: 162625.8145
Deduct 1995 from 2140 and we're left with 145.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1450, and continue the process.

On to step 13:
1450 divided by 399 is 3 with a remainder of 253.
Use 3 as the next digit of our solution. 
Result so far: 162625.81453
The remainder is 253 after subtracting 1197 from 1450.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2530, and continue the process.

Step 14:
399 goes into 2530 6 times with a remainder of 136.
The number 6 becomes the next digit in our result. 
Result so far: 162625.814536
Subtracting 2394 from 2530 leaves us with 136.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1360, and continue the process.

Advancing to step 15:
399 can be fit into 1360 3 times, resulting in a remainder of 163.
Use 3 as the next digit of our solution. 
Result so far: 162625.8145363
The remainder is 163 after subtracting 1197 from 1360.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1630, and continue the process.

Step 16:
1630 divided by 399 is 4 with a remainder of 34.
The number 4 becomes the next digit in our result. 
Result so far: 162625.81453634
The remainder is 34 after subtracting 1596 from 1630.
Since there are no more digits in the dividend, we add a zero to the remainder making it 340, and continue the process.

The final outcome is 162625.81453634, with a leftover of 3.4e-08.