642064 ÷ 21 
Our goal is to divide 642064 by 21.

Going ahead to step 1:
6 divided by 21 is 0 with a remainder of 6.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we subtract 0 from 6, we get 6.
Fetch the next digit (4) from the dividend, attach it to 6 and continue: 64 / 21

Moving on to step 2:
64 divided by 21 is 3 with a remainder of 1.
Record the quotient 3 as the next digit in the result. 
Result so far: 3.0
The remainder is 1 after subtracting 63 from 64.
Grab the next digit (2) from the dividend, add it to 1, then carry on: 12 / 21

Step 3:
If we divide 12 by 21, we get 0 and a remainder of 12.
Write down 0 as next digit of the result. 
Result so far: 30.0
If we take 0 away from 12, we end up with 12.
Take the next digit (0) from the dividend and append it to 12, then repeat: 120 / 21

Step 4:
120 divided by 21 is 5 with a remainder of 15.
The next digit of our result is 5. 
Result so far: 305.0
The remainder is 15 after subtracting 105 from 120.
Grab the next digit (6) from the dividend, add it to 15, then carry on: 156 / 21

Advancing to step 5:
21 can be fit into 156 7 times, resulting in a remainder of 9.
Put 7 as the next digit of the answer. 
Result so far: 3057.0
The remainder is 9 after subtracting 147 from 156.
Fetch the next digit (4) from the dividend, attach it to 9 and continue: 94 / 21

Going ahead to step 6:
When dividing 94 by 21, we get 4 with a remainder of 10.
Use 4 as the next digit of our solution. 
Result so far: 30574.0
Deduct 84 from 94 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.

Step 7:
If we divide 100 by 21, we get 4 and a remainder of 16.
Write down 4 as next digit of the result. 
Result so far: 30574.4
If we take 84 away from 100, we end up 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 8:
21 can be fit into 160 7 times, resulting in a remainder of 13.
Use 7 as the next digit of our solution. 
Result so far: 30574.47
Subtracting 147 from 160 leaves us 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.

Let's proceed to step 9:
130 divided by 21 is 6 with a remainder of 4.
Write down 6 as next digit of the result. 
Result so far: 30574.476
Subtracting 126 from 130 leaves us with 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Advancing to step 10:
The number 21 fits into 40 1 times, leaving a remainder of 19.
Use 1 as the next digit of our solution. 
Result so far: 30574.4761
If we take 21 away from 40, we end up with 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 11:
If we divide 190 by 21, we get 9 and a remainder of 1.
The next digit of our result is 9. 
Result so far: 30574.47619
Subtracting 189 from 190 leaves us with 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 12:
21 goes into 10 0 times with a remainder of 10.
The next digit of our result is 0. 
Result so far: 30574.47619
If we subtract 0 from 10, we 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.

On to step 13:
The number 21 fits into 100 4 times, leaving a remainder of 16.
The next digit of our result is 4. 
Result so far: 30574.4761904
If we take 84 away from 100, we end up 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.

On to step 14:
160 divided by 21 is 7 with a remainder of 13.
Record the quotient 7 as the next digit in the result. 
Result so far: 30574.47619047
If we subtract 147 from 160, we get 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

After the division, we end up with 30574.47619047 and a remainder of 1.3e-08.