3989109 divided by 821 
The aim is to understand the frequency of 821 in 3989109.

Going ahead to step 1:
When dividing 3 by 821, we get 0 with a remainder of 3.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Deduct 0 from 3 and we're left with 3.
Grab the next digit (9) from the dividend, add it to 3, then carry on: 39 / 821

On to step 2:
39 divided by 821 is 0 with a remainder of 39.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 39 and we're left with 39.
Append the next digit (8) from the dividend to 39 and continue with: 398 / 821

Step 3:
821 can be fit into 398 0 times, resulting in a remainder of 398.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we subtract 0 from 398, we get 398.
Include the next digit (9) from the dividend after 398, then repeat: 3989 / 821

Let's proceed to step 4:
821 can be fit into 3989 4 times, resulting in a remainder of 705.
The number 4 becomes the next digit in our result. 
Result so far: 4.0
Deduct 3284 from 3989 and we're left with 705.
Bring next digit (1) of the dividend behind the 705 and repeat the process: 7051 / 821

On to step 5:
The number 821 fits into 7051 8 times, leaving a remainder of 483.
The next digit of our result is 8. 
Result so far: 48.0
Deduct 6568 from 7051 and we're left with 483.
Fetch the next digit (0) from the dividend, attach it to 483 and continue: 4830 / 821

On to step 6:
If we divide 4830 by 821, we get 5 and a remainder of 725.
The number 5 becomes the next digit in our result. 
Result so far: 485.0
Subtract 4105 from 4830 to get 725.
Grab the next digit (9) from the dividend, add it to 725, then carry on: 7259 / 821

On to step 7:
If we divide 7259 by 821, we get 8 and a remainder of 691.
The next digit of our result is 8. 
Result so far: 4858.0
If we take 6568 away from 7259, we end up with 691.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6910, and continue the process.

On to step 8:
821 goes into 6910 8 times with a remainder of 342.
Put 8 as the next digit of the answer. 
Result so far: 4858.8
Subtracting 6568 from 6910 leaves us with 342.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3420, and continue the process.

Advancing to step 9:
The number 821 fits into 3420 4 times, leaving a remainder of 136.
Write down 4 as next digit of the result. 
Result so far: 4858.84
Subtract 3284 from 3420 to get 136.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1360, and continue the process.

Going ahead to step 10:
821 can be fit into 1360 1 times, resulting in a remainder of 539.
Record the quotient 1 as the next digit in the result. 
Result so far: 4858.841
Subtracting 821 from 1360 leaves us with 539.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5390, and continue the process.

Moving on to step 11:
The number 821 fits into 5390 6 times, leaving a remainder of 464.
Put 6 as the next digit of the answer. 
Result so far: 4858.8416
Subtract 4926 from 5390 to get 464.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4640, and continue the process.

Going ahead to step 12:
When dividing 4640 by 821, we get 5 with a remainder of 535.
The next digit of our result is 5. 
Result so far: 4858.84165
If we take 4105 away from 4640, we end up with 535.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5350, and continue the process.

Let's proceed to step 13:
When dividing 5350 by 821, we get 6 with a remainder of 424.
The number 6 becomes the next digit in our result. 
Result so far: 4858.841656
The remainder is 424 after subtracting 4926 from 5350.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4240, and continue the process.

On to step 14:
The number 821 fits into 4240 5 times, leaving a remainder of 135.
The number 5 becomes the next digit in our result. 
Result so far: 4858.8416565
If we subtract 4105 from 4240, we get 135.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1350, and continue the process.

Moving on to step 15:
If we divide 1350 by 821, we get 1 and a remainder of 529.
Write down 1 as next digit of the result. 
Result so far: 4858.84165651
The remainder is 529 after subtracting 821 from 1350.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5290, and continue the process.

The final result is 4858.84165651 with a remainder of 5.29e-07.