378274 ÷ 21 
We want to figure out the number of times 378274 can be divided by 21.

Moving on to step 1:
The number 21 fits into 3 0 times, leaving a remainder of 3.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we take 0 away from 3, we end up with 3.
Take the next digit (7) from the dividend and append it to 3, then repeat: 37 / 21

Moving on to step 2:
The number 21 fits into 37 1 times, leaving a remainder of 16.
The next digit of our result is 1. 
Result so far: 1.0
Subtracting 21 from 37 leaves us with 16.
Include the next digit (8) from the dividend after 16, then repeat: 168 / 21

Going ahead to step 3:
The number 21 fits into 168 8 times, leaving a remainder of 0.
Record the quotient 8 as the next digit in the result. 
Result so far: 18.0
If we subtract 168 from 168, we get 0.
Take the next digit (2) from the dividend and append it to 0, then repeat: 2 / 21

Moving on to step 4:
2 divided by 21 is 0 with a remainder of 2.
The next digit of our result is 0. 
Result so far: 180.0
The remainder is 2 after subtracting 0 from 2.
Fetch the next digit (7) from the dividend, attach it to 2 and continue: 27 / 21

Moving on to step 5:
The number 21 fits into 27 1 times, leaving a remainder of 6.
The number 1 becomes the next digit in our result. 
Result so far: 1801.0
The remainder is 6 after subtracting 21 from 27.
Take the next digit (4) from the dividend and append it to 6, then repeat: 64 / 21

Going ahead to step 6:
The number 21 fits into 64 3 times, leaving a remainder of 1.
Use 3 as the next digit of our solution. 
Result so far: 18013.0
Deduct 63 from 64 and we're left 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.

Let's proceed to step 7:
21 goes into 10 0 times with a remainder of 10.
Write down 0 as next digit of the result. 
Result so far: 18013.0
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.

Moving on to step 8:
21 goes into 100 4 times with a remainder of 16.
Put 4 as the next digit of the answer. 
Result so far: 18013.04
The remainder is 16 after subtracting 84 from 100.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

Moving on to step 9:
21 goes into 160 7 times with a remainder of 13.
The number 7 becomes the next digit in our result. 
Result so far: 18013.047
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 10:
When dividing 130 by 21, we get 6 with a remainder of 4.
The number 6 becomes the next digit in our result. 
Result so far: 18013.0476
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.

Step 11:
21 can be fit into 40 1 times, resulting in a remainder of 19.
The next digit of our result is 1. 
Result so far: 18013.04761
Subtracting 21 from 40 leaves us 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.

On to step 12:
190 divided by 21 is 9 with a remainder of 1.
Write down 9 as next digit of the result. 
Result so far: 18013.047619
If we take 189 away from 190, we end up 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 13:
10 divided by 21 is 0 with a remainder of 10.
The next digit of our result is 0. 
Result so far: 18013.047619
Subtracting 0 from 10 leaves us 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.

Going ahead to step 14:
The number 21 fits into 100 4 times, leaving a remainder of 16.
Use 4 as the next digit of our solution. 
Result so far: 18013.04761904
Subtract 84 from 100 to get 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

The final outcome is 18013.04761904, with a leftover of 1.6e-08.