640659 divided by 40 
Our goal is to divide 640659 by 40.

Moving on to step 1:
40 goes into 6 0 times with a remainder of 6.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Deduct 0 from 6 and we're left with 6.
Append the next digit (4) from the dividend to 6 and continue with: 64 / 40

Let's proceed to step 2:
The number 40 fits into 64 1 times, leaving a remainder of 24.
Use 1 as the next digit of our solution. 
Result so far: 1.0
The remainder is 24 after subtracting 40 from 64.
Take the next digit (0) from the dividend and append it to 24, then repeat: 240 / 40

Advancing to step 3:
40 goes into 240 6 times with a remainder of 0.
Write down 6 as next digit of the result. 
Result so far: 16.0
If we take 240 away from 240, we end up with 0.
Append the next digit (6) from the dividend to 0 and continue with: 6 / 40

Advancing to step 4:
6 divided by 40 is 0 with a remainder of 6.
The next digit of our result is 0. 
Result so far: 160.0
Subtract 0 from 6 to get 6.
Grab the next digit (5) from the dividend, add it to 6, then carry on: 65 / 40

Advancing to step 5:
When dividing 65 by 40, we get 1 with a remainder of 25.
Record the quotient 1 as the next digit in the result. 
Result so far: 1601.0
Subtracting 40 from 65 leaves us with 25.
Fetch the next digit (9) from the dividend, attach it to 25 and continue: 259 / 40

Moving on to step 6:
259 divided by 40 is 6 with a remainder of 19.
Write down 6 as next digit of the result. 
Result so far: 16016.0
If we take 240 away from 259, we end up with 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Moving on to step 7:
If we divide 190 by 40, we get 4 and a remainder of 30.
Put 4 as the next digit of the answer. 
Result so far: 16016.4
The remainder is 30 after subtracting 160 from 190.
Since there are no more digits in the dividend, we add a zero to the remainder making it 300, and continue the process.

Let's proceed to step 8:
If we divide 300 by 40, we get 7 and a remainder of 20.
The number 7 becomes the next digit in our result. 
Result so far: 16016.47
If we take 280 away from 300, we end up with 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

On to step 9:
When dividing 200 by 40, we get 5 with a remainder of 0.
Record the quotient 5 as the next digit in the result. 
Result so far: 16016.475
If we subtract 200 from 200, 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.

Let's proceed to step 10:
When dividing 0 by 40, we get 0 with a remainder of 0.
Write down 0 as next digit of the result. 
Result so far: 16016.475
Subtract 0 from 0 to 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.

Step 11:
If we divide 0 by 40, we get 0 and a remainder of 0.
Use 0 as the next digit of our solution. 
Result so far: 16016.475
Subtract 0 from 0 to 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.

The final outcome is 16016.475, with a leftover of 0.0.