Let's divide 68400064 by 21
We're looking to find how many times 21 goes into 68400064.

Step 1:
The number 21 fits into 6 0 times, leaving a remainder of 6.
The next digit of our result is 0. 
Result so far: 0.0
If we take 0 away from 6, we end up with 6.
Append the next digit (8) from the dividend to 6 and continue with: 68 / 21

Step 2:
If we divide 68 by 21, we get 3 and a remainder of 5.
The next digit of our result is 3. 
Result so far: 3.0
Deduct 63 from 68 and we're left with 5.
Grab the next digit (4) from the dividend, add it to 5, then carry on: 54 / 21

Advancing to step 3:
54 divided by 21 is 2 with a remainder of 12.
Put 2 as the next digit of the answer. 
Result so far: 32.0
If we subtract 42 from 54, we get 12.
Grab the next digit (0) from the dividend, add it to 12, then carry on: 120 / 21

On to step 4:
If we divide 120 by 21, we get 5 and a remainder of 15.
Use 5 as the next digit of our solution. 
Result so far: 325.0
Deduct 105 from 120 and we're left with 15.
Include the next digit (0) from the dividend after 15, then repeat: 150 / 21

Let's proceed to step 5:
The number 21 fits into 150 7 times, leaving a remainder of 3.
The next digit of our result is 7. 
Result so far: 3257.0
Subtract 147 from 150 to get 3.
Include the next digit (0) from the dividend after 3, then repeat: 30 / 21

Going ahead to step 6:
21 goes into 30 1 times with a remainder of 9.
Put 1 as the next digit of the answer. 
Result so far: 32571.0
Subtracting 21 from 30 leaves us with 9.
Take the next digit (6) from the dividend and append it to 9, then repeat: 96 / 21

On to step 7:
96 divided by 21 is 4 with a remainder of 12.
Write down 4 as next digit of the result. 
Result so far: 325714.0
If we subtract 84 from 96, we get 12.
Include the next digit (4) from the dividend after 12, then repeat: 124 / 21

Moving on to step 8:
21 can be fit into 124 5 times, resulting in a remainder of 19.
The number 5 becomes the next digit in our result. 
Result so far: 3257145.0
The remainder is 19 after subtracting 105 from 124.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Going ahead to step 9:
21 can be fit into 190 9 times, resulting in a remainder of 1.
Use 9 as the next digit of our solution. 
Result so far: 3257145.9
The remainder is 1 after subtracting 189 from 190.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

On to step 10:
10 divided by 21 is 0 with a remainder of 10.
The next digit of our result is 0. 
Result so far: 3257145.9
Subtract 0 from 10 to get 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Advancing to step 11:
21 can be fit into 100 4 times, resulting in a remainder of 16.
The next digit of our result is 4. 
Result so far: 3257145.904
Subtracting 84 from 100 leaves us with 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

Step 12:
21 goes into 160 7 times with a remainder of 13.
The next digit of our result is 7. 
Result so far: 3257145.9047
If we take 147 away from 160, we end up with 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

Going ahead to step 13:
21 goes into 130 6 times with a remainder of 4.
Write down 6 as next digit of the result. 
Result so far: 3257145.90476
The remainder is 4 after subtracting 126 from 130.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Going ahead to step 14:
40 divided by 21 is 1 with a remainder of 19.
The next digit of our result is 1. 
Result so far: 3257145.904761
Subtract 21 from 40 to get 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Advancing to step 15:
190 divided by 21 is 9 with a remainder of 1.
Write down 9 as next digit of the result. 
Result so far: 3257145.9047619
If we subtract 189 from 190, we get 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

On to step 16:
21 goes into 10 0 times with a remainder of 10.
Use 0 as the next digit of our solution. 
Result so far: 3257145.9047619
Deduct 0 from 10 and we're left with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

The quotient of the division is 3257145.9047619, and the remainder is 1e-08.