33875613 ÷ 644 
The aim is to understand the frequency of 644 in 33875613.

Step 1:
If we divide 3 by 644, we get 0 and a remainder of 3.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtract 0 from 3 to get 3.
Grab the next digit (3) from the dividend, add it to 3, then carry on: 33 / 644

On to step 2:
If we divide 33 by 644, we get 0 and a remainder of 33.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtract 0 from 33 to get 33.
Bring next digit (8) of the dividend behind the 33 and repeat the process: 338 / 644

Step 3:
If we divide 338 by 644, we get 0 and a remainder of 338.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we subtract 0 from 338, we get 338.
Include the next digit (7) from the dividend after 338, then repeat: 3387 / 644

Let's proceed to step 4:
644 goes into 3387 5 times with a remainder of 167.
Record the quotient 5 as the next digit in the result. 
Result so far: 5.0
Subtracting 3220 from 3387 leaves us with 167.
Bring next digit (5) of the dividend behind the 167 and repeat the process: 1675 / 644

Let's proceed to step 5:
1675 divided by 644 is 2 with a remainder of 387.
Put 2 as the next digit of the answer. 
Result so far: 52.0
Deduct 1288 from 1675 and we're left with 387.
Append the next digit (6) from the dividend to 387 and continue with: 3876 / 644

Going ahead to step 6:
644 goes into 3876 6 times with a remainder of 12.
The next digit of our result is 6. 
Result so far: 526.0
Subtracting 3864 from 3876 leaves us with 12.
Grab the next digit (1) from the dividend, add it to 12, then carry on: 121 / 644

Advancing to step 7:
If we divide 121 by 644, we get 0 and a remainder of 121.
Write down 0 as next digit of the result. 
Result so far: 5260.0
The remainder is 121 after subtracting 0 from 121.
Append the next digit (3) from the dividend to 121 and continue with: 1213 / 644

Step 8:
If we divide 1213 by 644, we get 1 and a remainder of 569.
The next digit of our result is 1. 
Result so far: 52601.0
Subtracting 644 from 1213 leaves us with 569.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5690, and continue the process.

Advancing to step 9:
644 can be fit into 5690 8 times, resulting in a remainder of 538.
Use 8 as the next digit of our solution. 
Result so far: 52601.8
Subtract 5152 from 5690 to get 538.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5380, and continue the process.

Going ahead to step 10:
When dividing 5380 by 644, we get 8 with a remainder of 228.
Write down 8 as next digit of the result. 
Result so far: 52601.88
If we subtract 5152 from 5380, we get 228.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2280, and continue the process.

The quotient of the division is 52601.88, and the remainder is 0.228.