Let's divide 643638 by 15
Our goal is to divide 643638 by 15.

Moving on to step 1:
15 goes into 6 0 times with a remainder of 6.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we take 0 away from 6, we end up with 6.
Grab the next digit (4) from the dividend, add it to 6, then carry on: 64 / 15

Advancing to step 2:
15 can be fit into 64 4 times, resulting in a remainder of 4.
Record the quotient 4 as the next digit in the result. 
Result so far: 4.0
If we take 60 away from 64, we end up with 4.
Take the next digit (3) from the dividend and append it to 4, then repeat: 43 / 15

Step 3:
15 can be fit into 43 2 times, resulting in a remainder of 13.
The number 2 becomes the next digit in our result. 
Result so far: 42.0
The remainder is 13 after subtracting 30 from 43.
Fetch the next digit (6) from the dividend, attach it to 13 and continue: 136 / 15

On to step 4:
15 goes into 136 9 times with a remainder of 1.
The number 9 becomes the next digit in our result. 
Result so far: 429.0
If we subtract 135 from 136, we get 1.
Take the next digit (3) from the dividend and append it to 1, then repeat: 13 / 15

Advancing to step 5:
The number 15 fits into 13 0 times, leaving a remainder of 13.
The number 0 becomes the next digit in our result. 
Result so far: 4290.0
If we subtract 0 from 13, we get 13.
Bring next digit (8) of the dividend behind the 13 and repeat the process: 138 / 15

Step 6:
15 goes into 138 9 times with a remainder of 3.
Record the quotient 9 as the next digit in the result. 
Result so far: 42909.0
If we subtract 135 from 138, we get 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Going ahead to step 7:
When dividing 30 by 15, we get 2 with a remainder of 0.
Put 2 as the next digit of the answer. 
Result so far: 42909.2
Deduct 30 from 30 and we're left with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Going ahead to step 8:
When dividing 0 by 15, we get 0 with a remainder of 0.
The number 0 becomes the next digit in our result. 
Result so far: 42909.2
Deduct 0 from 0 and we're left with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Step 9:
0 divided by 15 is 0 with a remainder of 0.
Put 0 as the next digit of the answer. 
Result so far: 42909.2
If we take 0 away from 0, we end up with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

The quotient of the division is 42909.2, and the remainder is 0.0.