903090 ÷ 7 
The aim is to understand the frequency of 7 in 903090.

Let's proceed to step 1:
The number 7 fits into 9 1 times, leaving a remainder of 2.
Put 1 as the next digit of the answer. 
Result so far: 1.0
If we take 7 away from 9, we end up with 2.
Include the next digit (0) from the dividend after 2, then repeat: 20 / 7

Going ahead to step 2:
20 divided by 7 is 2 with a remainder of 6.
The next digit of our result is 2. 
Result so far: 12.0
If we take 14 away from 20, we end up with 6.
Include the next digit (3) from the dividend after 6, then repeat: 63 / 7

Advancing to step 3:
When dividing 63 by 7, we get 9 with a remainder of 0.
Put 9 as the next digit of the answer. 
Result so far: 129.0
If we subtract 63 from 63, we get 0.
Grab the next digit (0) from the dividend, add it to 0, then carry on: 0 / 7

Advancing to step 4:
7 can be fit into 0 0 times, resulting in a remainder of 0.
Write down 0 as next digit of the result. 
Result so far: 1290.0
If we take 0 away from 0, we end up with 0.
Fetch the next digit (9) from the dividend, attach it to 0 and continue: 9 / 7

Let's proceed to step 5:
7 can be fit into 9 1 times, resulting in a remainder of 2.
The number 1 becomes the next digit in our result. 
Result so far: 12901.0
If we take 7 away from 9, we end up with 2.
Take the next digit (0) from the dividend and append it to 2, then repeat: 20 / 7

Let's proceed to step 6:
7 goes into 20 2 times with a remainder of 6.
Write down 2 as next digit of the result. 
Result so far: 129012.0
If we subtract 14 from 20, we get 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Let's proceed to step 7:
7 can be fit into 60 8 times, resulting in a remainder of 4.
Use 8 as the next digit of our solution. 
Result so far: 129012.8
If we take 56 away from 60, we end up with 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Step 8:
The number 7 fits into 40 5 times, leaving a remainder of 5.
The next digit of our result is 5. 
Result so far: 129012.85
Subtracting 35 from 40 leaves us with 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Let's proceed to step 9:
If we divide 50 by 7, we get 7 and a remainder of 1.
Use 7 as the next digit of our solution. 
Result so far: 129012.857
If we subtract 49 from 50, we get 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

On to step 10:
7 goes into 10 1 times with a remainder of 3.
Use 1 as the next digit of our solution. 
Result so far: 129012.8571
If we take 7 away from 10, we end up with 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Step 11:
If we divide 30 by 7, we get 4 and a remainder of 2.
The number 4 becomes the next digit in our result. 
Result so far: 129012.85714
If we subtract 28 from 30, we get 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Step 12:
7 can be fit into 20 2 times, resulting in a remainder of 6.
Use 2 as the next digit of our solution. 
Result so far: 129012.857142
Deduct 14 from 20 and we're left 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.

Let's proceed to step 13:
7 goes into 60 8 times with a remainder of 4.
The next digit of our result is 8. 
Result so far: 129012.8571428
The remainder is 4 after subtracting 56 from 60.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

On to step 14:
When dividing 40 by 7, we get 5 with a remainder of 5.
The number 5 becomes the next digit in our result. 
Result so far: 129012.85714285
If we take 35 away from 40, we end up with 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

The final outcome is 129012.85714285, with a leftover of 5e-09.