We look at the division of 98778240 by 21 
We want to figure out the number of times 98778240 can be divided by 21.

On to step 1:
The number 21 fits into 9 0 times, leaving a remainder of 9.
Write down 0 as next digit of the result. 
Result so far: 0.0
Deduct 0 from 9 and we're left with 9.
Fetch the next digit (8) from the dividend, attach it to 9 and continue: 98 / 21

Moving on to step 2:
98 divided by 21 is 4 with a remainder of 14.
Write down 4 as next digit of the result. 
Result so far: 4.0
The remainder is 14 after subtracting 84 from 98.
Grab the next digit (7) from the dividend, add it to 14, then carry on: 147 / 21

On to step 3:
If we divide 147 by 21, we get 7 and a remainder of 0.
Use 7 as the next digit of our solution. 
Result so far: 47.0
Subtract 147 from 147 to get 0.
Bring next digit (7) of the dividend behind the 0 and repeat the process: 7 / 21

Step 4:
21 goes into 7 0 times with a remainder of 7.
The next digit of our result is 0. 
Result so far: 470.0
The remainder is 7 after subtracting 0 from 7.
Fetch the next digit (8) from the dividend, attach it to 7 and continue: 78 / 21

Going ahead to step 5:
When dividing 78 by 21, we get 3 with a remainder of 15.
The next digit of our result is 3. 
Result so far: 4703.0
Subtract 63 from 78 to get 15.
Append the next digit (2) from the dividend to 15 and continue with: 152 / 21

Advancing to step 6:
The number 21 fits into 152 7 times, leaving a remainder of 5.
Write down 7 as next digit of the result. 
Result so far: 47037.0
Deduct 147 from 152 and we're left with 5.
Include the next digit (4) from the dividend after 5, then repeat: 54 / 21

Let's proceed to step 7:
21 can be fit into 54 2 times, resulting in a remainder of 12.
Record the quotient 2 as the next digit in the result. 
Result so far: 470372.0
Deduct 42 from 54 and we're left with 12.
Take the next digit (0) from the dividend and append it to 12, then repeat: 120 / 21

On to step 8:
The number 21 fits into 120 5 times, leaving a remainder of 15.
The number 5 becomes the next digit in our result. 
Result so far: 4703725.0
Subtract 105 from 120 to get 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Moving on to step 9:
If we divide 150 by 21, we get 7 and a remainder of 3.
Put 7 as the next digit of the answer. 
Result so far: 4703725.7
Subtracting 147 from 150 leaves us with 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Advancing to step 10:
21 can be fit into 30 1 times, resulting in a remainder of 9.
Put 1 as the next digit of the answer. 
Result so far: 4703725.71
Subtracting 21 from 30 leaves us with 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Advancing to step 11:
When dividing 90 by 21, we get 4 with a remainder of 6.
Write down 4 as next digit of the result. 
Result so far: 4703725.714
If we take 84 away from 90, we end up with 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Going ahead to step 12:
The number 21 fits into 60 2 times, leaving a remainder of 18.
Write down 2 as next digit of the result. 
Result so far: 4703725.7142
Subtracting 42 from 60 leaves us with 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

Step 13:
21 goes into 180 8 times with a remainder of 12.
Write down 8 as next digit of the result. 
Result so far: 4703725.71428
Deduct 168 from 180 and we're left with 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Moving on to step 14:
If we divide 120 by 21, we get 5 and a remainder of 15.
Record the quotient 5 as the next digit in the result. 
Result so far: 4703725.714285
Subtract 105 from 120 to get 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Let's proceed to step 15:
The number 21 fits into 150 7 times, leaving a remainder of 3.
Record the quotient 7 as the next digit in the result. 
Result so far: 4703725.7142857
If we take 147 away from 150, we end up with 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Going ahead to step 16:
21 can be fit into 30 1 times, resulting in a remainder of 9.
The number 1 becomes the next digit in our result. 
Result so far: 4703725.71428571
Subtract 21 from 30 to get 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

The final result is 4703725.71428571 with a remainder of 9e-09.