990010 ÷ 13 
The aim is to understand the frequency of 13 in 990010.

Advancing to step 1:
9 divided by 13 is 0 with a remainder of 9.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we take 0 away from 9, we end up with 9.
Append the next digit (9) from the dividend to 9 and continue with: 99 / 13

On to step 2:
If we divide 99 by 13, we get 7 and a remainder of 8.
Use 7 as the next digit of our solution. 
Result so far: 7.0
Subtract 91 from 99 to get 8.
Grab the next digit (0) from the dividend, add it to 8, then carry on: 80 / 13

Advancing to step 3:
13 goes into 80 6 times with a remainder of 2.
The next digit of our result is 6. 
Result so far: 76.0
The remainder is 2 after subtracting 78 from 80.
Append the next digit (0) from the dividend to 2 and continue with: 20 / 13

Going ahead to step 4:
When dividing 20 by 13, we get 1 with a remainder of 7.
Record the quotient 1 as the next digit in the result. 
Result so far: 761.0
If we take 13 away from 20, we end up with 7.
Fetch the next digit (1) from the dividend, attach it to 7 and continue: 71 / 13

On to step 5:
When dividing 71 by 13, we get 5 with a remainder of 6.
Write down 5 as next digit of the result. 
Result so far: 7615.0
The remainder is 6 after subtracting 65 from 71.
Grab the next digit (0) from the dividend, add it to 6, then carry on: 60 / 13

Step 6:
If we divide 60 by 13, we get 4 and a remainder of 8.
Use 4 as the next digit of our solution. 
Result so far: 76154.0
If we subtract 52 from 60, we get 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

On to step 7:
When dividing 80 by 13, we get 6 with a remainder of 2.
The next digit of our result is 6. 
Result so far: 76154.6
Deduct 78 from 80 and we're left with 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Advancing to step 8:
13 goes into 20 1 times with a remainder of 7.
The next digit of our result is 1. 
Result so far: 76154.61
If we subtract 13 from 20, we get 7.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

Moving on to step 9:
13 goes into 70 5 times with a remainder of 5.
Record the quotient 5 as the next digit in the result. 
Result so far: 76154.615
Subtract 65 from 70 to get 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Going ahead to step 10:
13 can be fit into 50 3 times, resulting in a remainder of 11.
The next digit of our result is 3. 
Result so far: 76154.6153
If we take 39 away from 50, we end up with 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Let's proceed to step 11:
110 divided by 13 is 8 with a remainder of 6.
The number 8 becomes the next digit in our result. 
Result so far: 76154.61538
Subtracting 104 from 110 leaves us with 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Step 12:
13 goes into 60 4 times with a remainder of 8.
The number 4 becomes the next digit in our result. 
Result so far: 76154.615384
Subtract 52 from 60 to get 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Going ahead to step 13:
80 divided by 13 is 6 with a remainder of 2.
Record the quotient 6 as the next digit in the result. 
Result so far: 76154.6153846
The remainder is 2 after subtracting 78 from 80.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Going ahead to step 14:
When dividing 20 by 13, we get 1 with a remainder of 7.
The next digit of our result is 1. 
Result so far: 76154.61538461
Subtracting 13 from 20 leaves us with 7.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

Our division results in 76154.61538461 with a remaining 7e-09.