643933 ÷ 40 
We're looking to find how many times 40 goes into 643933.

Moving on to step 1:
When dividing 6 by 40, we get 0 with a remainder of 6.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtracting 0 from 6 leaves us with 6.
Take the next digit (4) from the dividend and append it to 6, then repeat: 64 / 40

On to step 2:
40 can be fit into 64 1 times, resulting in a remainder of 24.
Use 1 as the next digit of our solution. 
Result so far: 1.0
If we subtract 40 from 64, we get 24.
Take the next digit (3) from the dividend and append it to 24, then repeat: 243 / 40

Moving on to step 3:
243 divided by 40 is 6 with a remainder of 3.
The number 6 becomes the next digit in our result. 
Result so far: 16.0
The remainder is 3 after subtracting 240 from 243.
Bring next digit (9) of the dividend behind the 3 and repeat the process: 39 / 40

On to step 4:
39 divided by 40 is 0 with a remainder of 39.
Put 0 as the next digit of the answer. 
Result so far: 160.0
If we take 0 away from 39, we end up with 39.
Include the next digit (3) from the dividend after 39, then repeat: 393 / 40

Going ahead to step 5:
40 goes into 393 9 times with a remainder of 33.
Write down 9 as next digit of the result. 
Result so far: 1609.0
If we subtract 360 from 393, we get 33.
Bring next digit (3) of the dividend behind the 33 and repeat the process: 333 / 40

Moving on to step 6:
When dividing 333 by 40, we get 8 with a remainder of 13.
The next digit of our result is 8. 
Result so far: 16098.0
Deduct 320 from 333 and we're left with 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

Let's proceed to step 7:
40 goes into 130 3 times with a remainder of 10.
The number 3 becomes the next digit in our result. 
Result so far: 16098.3
Deduct 120 from 130 and we're left with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Going ahead to step 8:
When dividing 100 by 40, we get 2 with a remainder of 20.
Record the quotient 2 as the next digit in the result. 
Result so far: 16098.32
If we subtract 80 from 100, we get 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Going ahead to step 9:
40 can be fit into 200 5 times, resulting in a remainder of 0.
The next digit of our result is 5. 
Result so far: 16098.325
Subtracting 200 from 200 leaves us 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 10:
The number 40 fits into 0 0 times, leaving a remainder of 0.
Record the quotient 0 as the next digit in the result. 
Result so far: 16098.325
If we subtract 0 from 0, we get 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Moving on to step 11:
0 divided by 40 is 0 with a remainder of 0.
Write down 0 as next digit of the result. 
Result so far: 16098.325
The remainder is 0 after subtracting 0 from 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 final result is 16098.325 with a remainder of 0.0.