We look at the division of 98421718 by 643 
We want to figure out the number of times 98421718 can be divided by 643.

Advancing to step 1:
If we divide 9 by 643, we get 0 and a remainder of 9.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we take 0 away from 9, we end up with 9.
Grab the next digit (8) from the dividend, add it to 9, then carry on: 98 / 643

Let's proceed to step 2:
The number 643 fits into 98 0 times, leaving a remainder of 98.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we take 0 away from 98, we end up with 98.
Bring next digit (4) of the dividend behind the 98 and repeat the process: 984 / 643

Moving on to step 3:
If we divide 984 by 643, we get 1 and a remainder of 341.
Record the quotient 1 as the next digit in the result. 
Result so far: 1.0
Deduct 643 from 984 and we're left with 341.
Bring next digit (2) of the dividend behind the 341 and repeat the process: 3412 / 643

Advancing to step 4:
When dividing 3412 by 643, we get 5 with a remainder of 197.
Write down 5 as next digit of the result. 
Result so far: 15.0
Subtracting 3215 from 3412 leaves us with 197.
Append the next digit (1) from the dividend to 197 and continue with: 1971 / 643

On to step 5:
The number 643 fits into 1971 3 times, leaving a remainder of 42.
Write down 3 as next digit of the result. 
Result so far: 153.0
If we subtract 1929 from 1971, we get 42.
Grab the next digit (7) from the dividend, add it to 42, then carry on: 427 / 643

On to step 6:
643 can be fit into 427 0 times, resulting in a remainder of 427.
The number 0 becomes the next digit in our result. 
Result so far: 1530.0
Subtracting 0 from 427 leaves us with 427.
Take the next digit (1) from the dividend and append it to 427, then repeat: 4271 / 643

Going ahead to step 7:
The number 643 fits into 4271 6 times, leaving a remainder of 413.
Record the quotient 6 as the next digit in the result. 
Result so far: 15306.0
Subtract 3858 from 4271 to get 413.
Append the next digit (8) from the dividend to 413 and continue with: 4138 / 643

Advancing to step 8:
If we divide 4138 by 643, we get 6 and a remainder of 280.
Use 6 as the next digit of our solution. 
Result so far: 153066.0
If we take 3858 away from 4138, we end up with 280.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2800, and continue the process.

Advancing to step 9:
The number 643 fits into 2800 4 times, leaving a remainder of 228.
Put 4 as the next digit of the answer. 
Result so far: 153066.4
Subtracting 2572 from 2800 leaves us with 228.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2280, and continue the process.

On to step 10:
When dividing 2280 by 643, we get 3 with a remainder of 351.
Write down 3 as next digit of the result. 
Result so far: 153066.43
Subtract 1929 from 2280 to get 351.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3510, and continue the process.

Moving on to step 11:
643 can be fit into 3510 5 times, resulting in a remainder of 295.
Record the quotient 5 as the next digit in the result. 
Result so far: 153066.435
Subtracting 3215 from 3510 leaves us with 295.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2950, and continue the process.

Moving on to step 12:
643 goes into 2950 4 times with a remainder of 378.
Record the quotient 4 as the next digit in the result. 
Result so far: 153066.4354
The remainder is 378 after subtracting 2572 from 2950.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3780, and continue the process.

Moving on to step 13:
643 goes into 3780 5 times with a remainder of 565.
Write down 5 as next digit of the result. 
Result so far: 153066.43545
Deduct 3215 from 3780 and we're left with 565.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5650, and continue the process.

Moving on to step 14:
The number 643 fits into 5650 8 times, leaving a remainder of 506.
Put 8 as the next digit of the answer. 
Result so far: 153066.435458
The remainder is 506 after subtracting 5144 from 5650.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5060, and continue the process.

Step 15:
643 can be fit into 5060 7 times, resulting in a remainder of 559.
The number 7 becomes the next digit in our result. 
Result so far: 153066.4354587
If we take 4501 away from 5060, we end up with 559.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5590, and continue the process.

Moving on to step 16:
5590 divided by 643 is 8 with a remainder of 446.
Write down 8 as next digit of the result. 
Result so far: 153066.43545878
If we take 5144 away from 5590, we end up with 446.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4460, and continue the process.

The final result is 153066.43545878 with a remainder of 4.46e-07.