25383213 ÷ 643 
We're looking to find how many times 643 goes into 25383213.

Moving on to step 1:
When dividing 2 by 643, we get 0 with a remainder of 2.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtract 0 from 2 to get 2.
Append the next digit (5) from the dividend to 2 and continue with: 25 / 643

Going ahead to step 2:
When dividing 25 by 643, we get 0 with a remainder of 25.
Write down 0 as next digit of the result. 
Result so far: 0.0
Deduct 0 from 25 and we're left with 25.
Bring next digit (3) of the dividend behind the 25 and repeat the process: 253 / 643

On to step 3:
When dividing 253 by 643, we get 0 with a remainder of 253.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we subtract 0 from 253, we get 253.
Append the next digit (8) from the dividend to 253 and continue with: 2538 / 643

Moving on to step 4:
The number 643 fits into 2538 3 times, leaving a remainder of 609.
The next digit of our result is 3. 
Result so far: 3.0
The remainder is 609 after subtracting 1929 from 2538.
Take the next digit (3) from the dividend and append it to 609, then repeat: 6093 / 643

Advancing to step 5:
643 goes into 6093 9 times with a remainder of 306.
The next digit of our result is 9. 
Result so far: 39.0
If we take 5787 away from 6093, we end up with 306.
Fetch the next digit (2) from the dividend, attach it to 306 and continue: 3062 / 643

Going ahead to step 6:
643 goes into 3062 4 times with a remainder of 490.
The number 4 becomes the next digit in our result. 
Result so far: 394.0
Subtracting 2572 from 3062 leaves us with 490.
Append the next digit (1) from the dividend to 490 and continue with: 4901 / 643

Step 7:
The number 643 fits into 4901 7 times, leaving a remainder of 400.
Write down 7 as next digit of the result. 
Result so far: 3947.0
Subtract 4501 from 4901 to get 400.
Bring next digit (3) of the dividend behind the 400 and repeat the process: 4003 / 643

Step 8:
643 goes into 4003 6 times with a remainder of 145.
Record the quotient 6 as the next digit in the result. 
Result so far: 39476.0
If we take 3858 away from 4003, we end up with 145.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1450, and continue the process.

Moving on to step 9:
If we divide 1450 by 643, we get 2 and a remainder of 164.
The next digit of our result is 2. 
Result so far: 39476.2
If we take 1286 away from 1450, we end up with 164.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1640, and continue the process.

Step 10:
643 goes into 1640 2 times with a remainder of 354.
The number 2 becomes the next digit in our result. 
Result so far: 39476.22
Subtracting 1286 from 1640 leaves us with 354.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3540, and continue the process.

The final result is 39476.22 with a remainder of 0.354.