We look at the division of 89185986 by 643 
We want to figure out the number of times 89185986 can be divided by 643.

Step 1:
643 can be fit into 8 0 times, resulting in a remainder of 8.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 8 and we're left with 8.
Append the next digit (9) from the dividend to 8 and continue with: 89 / 643

On to step 2:
643 can be fit into 89 0 times, resulting in a remainder of 89.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we subtract 0 from 89, we get 89.
Include the next digit (1) from the dividend after 89, then repeat: 891 / 643

Going ahead to step 3:
891 divided by 643 is 1 with a remainder of 248.
The next digit of our result is 1. 
Result so far: 1.0
If we subtract 643 from 891, we get 248.
Fetch the next digit (8) from the dividend, attach it to 248 and continue: 2488 / 643

Moving on to step 4:
643 goes into 2488 3 times with a remainder of 559.
The number 3 becomes the next digit in our result. 
Result so far: 13.0
If we subtract 1929 from 2488, we get 559.
Fetch the next digit (5) from the dividend, attach it to 559 and continue: 5595 / 643

On to step 5:
If we divide 5595 by 643, we get 8 and a remainder of 451.
Write down 8 as next digit of the result. 
Result so far: 138.0
If we subtract 5144 from 5595, we get 451.
Append the next digit (9) from the dividend to 451 and continue with: 4519 / 643

Moving on to step 6:
If we divide 4519 by 643, we get 7 and a remainder of 18.
Record the quotient 7 as the next digit in the result. 
Result so far: 1387.0
The remainder is 18 after subtracting 4501 from 4519.
Include the next digit (8) from the dividend after 18, then repeat: 188 / 643

Step 7:
When dividing 188 by 643, we get 0 with a remainder of 188.
The number 0 becomes the next digit in our result. 
Result so far: 13870.0
Subtract 0 from 188 to get 188.
Include the next digit (6) from the dividend after 188, then repeat: 1886 / 643

Advancing to step 8:
643 can be fit into 1886 2 times, resulting in a remainder of 600.
Write down 2 as next digit of the result. 
Result so far: 138702.0
If we subtract 1286 from 1886, we get 600.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6000, and continue the process.

Advancing to step 9:
The number 643 fits into 6000 9 times, leaving a remainder of 213.
The number 9 becomes the next digit in our result. 
Result so far: 138702.9
The remainder is 213 after subtracting 5787 from 6000.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2130, and continue the process.

Moving on to step 10:
643 can be fit into 2130 3 times, resulting in a remainder of 201.
The next digit of our result is 3. 
Result so far: 138702.93
Deduct 1929 from 2130 and we're left with 201.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2010, and continue the process.

Moving on to step 11:
643 goes into 2010 3 times with a remainder of 81.
The number 3 becomes the next digit in our result. 
Result so far: 138702.933
If we take 1929 away from 2010, we end up with 81.
Since there are no more digits in the dividend, we add a zero to the remainder making it 810, and continue the process.

Our division results in 138702.933 with a remaining 0.0081.