We're dividing 98121665 by 643 
We're looking to find how many times 643 goes into 98121665.

Going ahead to step 1:
If we divide 9 by 643, we get 0 and a remainder of 9.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtracting 0 from 9 leaves us with 9.
Append the next digit (8) from the dividend to 9 and continue with: 98 / 643

On to step 2:
643 can be fit into 98 0 times, resulting in a remainder of 98.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 98 and we're left with 98.
Append the next digit (1) from the dividend to 98 and continue with: 981 / 643

Moving on to step 3:
If we divide 981 by 643, we get 1 and a remainder of 338.
The number 1 becomes the next digit in our result. 
Result so far: 1.0
If we subtract 643 from 981, we get 338.
Bring next digit (2) of the dividend behind the 338 and repeat the process: 3382 / 643

Advancing to step 4:
3382 divided by 643 is 5 with a remainder of 167.
Use 5 as the next digit of our solution. 
Result so far: 15.0
The remainder is 167 after subtracting 3215 from 3382.
Take the next digit (1) from the dividend and append it to 167, then repeat: 1671 / 643

Moving on to step 5:
643 goes into 1671 2 times with a remainder of 385.
Record the quotient 2 as the next digit in the result. 
Result so far: 152.0
Subtracting 1286 from 1671 leaves us with 385.
Take the next digit (6) from the dividend and append it to 385, then repeat: 3856 / 643

Let's proceed to step 6:
3856 divided by 643 is 5 with a remainder of 641.
Use 5 as the next digit of our solution. 
Result so far: 1525.0
The remainder is 641 after subtracting 3215 from 3856.
Fetch the next digit (6) from the dividend, attach it to 641 and continue: 6416 / 643

Let's proceed to step 7:
643 can be fit into 6416 9 times, resulting in a remainder of 629.
Write down 9 as next digit of the result. 
Result so far: 15259.0
Subtract 5787 from 6416 to get 629.
Take the next digit (5) from the dividend and append it to 629, then repeat: 6295 / 643

Going ahead to step 8:
If we divide 6295 by 643, we get 9 and a remainder of 508.
Write down 9 as next digit of the result. 
Result so far: 152599.0
If we subtract 5787 from 6295, we get 508.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5080, and continue the process.

Moving on to step 9:
643 goes into 5080 7 times with a remainder of 579.
Write down 7 as next digit of the result. 
Result so far: 152599.7
Deduct 4501 from 5080 and we're left with 579.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5790, and continue the process.

Going ahead to step 10:
643 can be fit into 5790 9 times, resulting in a remainder of 3.
Record the quotient 9 as the next digit in the result. 
Result so far: 152599.79
The remainder is 3 after subtracting 5787 from 5790.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Moving on to step 11:
643 goes into 30 0 times with a remainder of 30.
Record the quotient 0 as the next digit in the result. 
Result so far: 152599.79
Deduct 0 from 30 and we're left with 30.
Since there are no more digits in the dividend, we add a zero to the remainder making it 300, and continue the process.

Step 12:
643 goes into 300 0 times with a remainder of 300.
The number 0 becomes the next digit in our result. 
Result so far: 152599.79
If we subtract 0 from 300, we get 300.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3000, and continue the process.

The final result is 152599.79 with a remainder of 0.003.