Let's divide 643658 by 90
Let's see how many times 90 fits into 643658.

Going ahead to step 1:
6 divided by 90 is 0 with a remainder of 6.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 6 and we're left with 6.
Fetch the next digit (4) from the dividend, attach it to 6 and continue: 64 / 90

Moving on to step 2:
The number 90 fits into 64 0 times, leaving a remainder of 64.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtract 0 from 64 to get 64.
Grab the next digit (3) from the dividend, add it to 64, then carry on: 643 / 90

Step 3:
90 goes into 643 7 times with a remainder of 13.
Put 7 as the next digit of the answer. 
Result so far: 7.0
The remainder is 13 after subtracting 630 from 643.
Take the next digit (6) from the dividend and append it to 13, then repeat: 136 / 90

Step 4:
The number 90 fits into 136 1 times, leaving a remainder of 46.
Use 1 as the next digit of our solution. 
Result so far: 71.0
Subtracting 90 from 136 leaves us with 46.
Grab the next digit (5) from the dividend, add it to 46, then carry on: 465 / 90

Moving on to step 5:
If we divide 465 by 90, we get 5 and a remainder of 15.
Put 5 as the next digit of the answer. 
Result so far: 715.0
If we subtract 450 from 465, we get 15.
Take the next digit (8) from the dividend and append it to 15, then repeat: 158 / 90

Let's proceed to step 6:
90 goes into 158 1 times with a remainder of 68.
Write down 1 as next digit of the result. 
Result so far: 7151.0
If we take 90 away from 158, we end up with 68.
Since there are no more digits in the dividend, we add a zero to the remainder making it 680, and continue the process.

Going ahead to step 7:
90 can be fit into 680 7 times, resulting in a remainder of 50.
The next digit of our result is 7. 
Result so far: 7151.7
The remainder is 50 after subtracting 630 from 680.
Since there are no more digits in the dividend, we add a zero to the remainder making it 500, and continue the process.

Step 8:
90 goes into 500 5 times with a remainder of 50.
The next digit of our result is 5. 
Result so far: 7151.75
If we take 450 away from 500, we end up with 50.
Since there are no more digits in the dividend, we add a zero to the remainder making it 500, and continue the process.

Moving on to step 9:
If we divide 500 by 90, we get 5 and a remainder of 50.
The number 5 becomes the next digit in our result. 
Result so far: 7151.755
Subtract 450 from 500 to get 50.
Since there are no more digits in the dividend, we add a zero to the remainder making it 500, and continue the process.

Our division results in 7151.755 with a remaining 0.005.