We're dividing 645840 by 43 
We're looking to find how many times 43 goes into 645840.

Advancing to step 1:
When dividing 6 by 43, we get 0 with a remainder of 6.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
The remainder is 6 after subtracting 0 from 6.
Bring next digit (4) of the dividend behind the 6 and repeat the process: 64 / 43

Going ahead to step 2:
43 can be fit into 64 1 times, resulting in a remainder of 21.
Write down 1 as next digit of the result. 
Result so far: 1.0
Subtracting 43 from 64 leaves us with 21.
Take the next digit (5) from the dividend and append it to 21, then repeat: 215 / 43

Going ahead to step 3:
The number 43 fits into 215 5 times, leaving a remainder of 0.
The number 5 becomes the next digit in our result. 
Result so far: 15.0
The remainder is 0 after subtracting 215 from 215.
Take the next digit (8) from the dividend and append it to 0, then repeat: 8 / 43

Advancing to step 4:
43 goes into 8 0 times with a remainder of 8.
Write down 0 as next digit of the result. 
Result so far: 150.0
Subtracting 0 from 8 leaves us with 8.
Fetch the next digit (4) from the dividend, attach it to 8 and continue: 84 / 43

Going ahead to step 5:
84 divided by 43 is 1 with a remainder of 41.
The number 1 becomes the next digit in our result. 
Result so far: 1501.0
Subtracting 43 from 84 leaves us with 41.
Grab the next digit (0) from the dividend, add it to 41, then carry on: 410 / 43

Moving on to step 6:
410 divided by 43 is 9 with a remainder of 23.
Write down 9 as next digit of the result. 
Result so far: 15019.0
Subtracting 387 from 410 leaves us with 23.
Since there are no more digits in the dividend, we add a zero to the remainder making it 230, and continue the process.

Step 7:
43 can be fit into 230 5 times, resulting in a remainder of 15.
Use 5 as the next digit of our solution. 
Result so far: 15019.5
If we subtract 215 from 230, we get 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Step 8:
150 divided by 43 is 3 with a remainder of 21.
The number 3 becomes the next digit in our result. 
Result so far: 15019.53
If we subtract 129 from 150, we get 21.
Since there are no more digits in the dividend, we add a zero to the remainder making it 210, and continue the process.

Moving on to step 9:
43 can be fit into 210 4 times, resulting in a remainder of 38.
Use 4 as the next digit of our solution. 
Result so far: 15019.534
Deduct 172 from 210 and we're left with 38.
Since there are no more digits in the dividend, we add a zero to the remainder making it 380, and continue the process.

On to step 10:
43 goes into 380 8 times with a remainder of 36.
The next digit of our result is 8. 
Result so far: 15019.5348
Subtract 344 from 380 to get 36.
Since there are no more digits in the dividend, we add a zero to the remainder making it 360, and continue the process.

On to step 11:
When dividing 360 by 43, we get 8 with a remainder of 16.
Record the quotient 8 as the next digit in the result. 
Result so far: 15019.53488
The remainder is 16 after subtracting 344 from 360.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

The final outcome is 15019.53488, with a leftover of 1.6e-05.