We're dividing 3581870 by 813 
The aim is to understand the frequency of 813 in 3581870.

On to step 1:
813 goes into 3 0 times with a remainder of 3.
The next digit of our result is 0. 
Result so far: 0.0
Subtract 0 from 3 to get 3.
Append the next digit (5) from the dividend to 3 and continue with: 35 / 813

Let's proceed to step 2:
If we divide 35 by 813, we get 0 and a remainder of 35.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we subtract 0 from 35, we get 35.
Take the next digit (8) from the dividend and append it to 35, then repeat: 358 / 813

On to step 3:
If we divide 358 by 813, we get 0 and a remainder of 358.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
The remainder is 358 after subtracting 0 from 358.
Fetch the next digit (1) from the dividend, attach it to 358 and continue: 3581 / 813

On to step 4:
The number 813 fits into 3581 4 times, leaving a remainder of 329.
The next digit of our result is 4. 
Result so far: 4.0
Subtracting 3252 from 3581 leaves us with 329.
Grab the next digit (8) from the dividend, add it to 329, then carry on: 3298 / 813

Moving on to step 5:
813 can be fit into 3298 4 times, resulting in a remainder of 46.
Write down 4 as next digit of the result. 
Result so far: 44.0
If we take 3252 away from 3298, we end up with 46.
Take the next digit (7) from the dividend and append it to 46, then repeat: 467 / 813

Let's proceed to step 6:
When dividing 467 by 813, we get 0 with a remainder of 467.
Put 0 as the next digit of the answer. 
Result so far: 440.0
Deduct 0 from 467 and we're left with 467.
Take the next digit (0) from the dividend and append it to 467, then repeat: 4670 / 813

On to step 7:
4670 divided by 813 is 5 with a remainder of 605.
Write down 5 as next digit of the result. 
Result so far: 4405.0
Subtracting 4065 from 4670 leaves us with 605.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6050, and continue the process.

Advancing to step 8:
The number 813 fits into 6050 7 times, leaving a remainder of 359.
Write down 7 as next digit of the result. 
Result so far: 4405.7
Subtract 5691 from 6050 to get 359.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3590, and continue the process.

On to step 9:
When dividing 3590 by 813, we get 4 with a remainder of 338.
The number 4 becomes the next digit in our result. 
Result so far: 4405.74
If we subtract 3252 from 3590, we get 338.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3380, and continue the process.

Step 10:
813 goes into 3380 4 times with a remainder of 128.
The number 4 becomes the next digit in our result. 
Result so far: 4405.744
Subtract 3252 from 3380 to get 128.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1280, and continue the process.

The quotient of the division is 4405.744, and the remainder is 0.0128.