We look at the division of 402378 by 90 
We want to divide 402378 by 90.

Let's proceed to step 1:
90 goes into 4 0 times with a remainder of 4.
The next digit of our result is 0. 
Result so far: 0.0
Subtracting 0 from 4 leaves us with 4.
Include the next digit (0) from the dividend after 4, then repeat: 40 / 90

Let's proceed to step 2:
When dividing 40 by 90, we get 0 with a remainder of 40.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
The remainder is 40 after subtracting 0 from 40.
Append the next digit (2) from the dividend to 40 and continue with: 402 / 90

Advancing to step 3:
90 goes into 402 4 times with a remainder of 42.
Record the quotient 4 as the next digit in the result. 
Result so far: 4.0
If we take 360 away from 402, we end up with 42.
Take the next digit (3) from the dividend and append it to 42, then repeat: 423 / 90

Advancing to step 4:
423 divided by 90 is 4 with a remainder of 63.
The next digit of our result is 4. 
Result so far: 44.0
If we subtract 360 from 423, we get 63.
Fetch the next digit (7) from the dividend, attach it to 63 and continue: 637 / 90

Going ahead to step 5:
If we divide 637 by 90, we get 7 and a remainder of 7.
Write down 7 as next digit of the result. 
Result so far: 447.0
Deduct 630 from 637 and we're left with 7.
Include the next digit (8) from the dividend after 7, then repeat: 78 / 90

On to step 6:
When dividing 78 by 90, we get 0 with a remainder of 78.
Use 0 as the next digit of our solution. 
Result so far: 4470.0
The remainder is 78 after subtracting 0 from 78.
Since there are no more digits in the dividend, we add a zero to the remainder making it 780, and continue the process.

Moving on to step 7:
When dividing 780 by 90, we get 8 with a remainder of 60.
Write down 8 as next digit of the result. 
Result so far: 4470.8
Subtracting 720 from 780 leaves us with 60.
Since there are no more digits in the dividend, we add a zero to the remainder making it 600, and continue the process.

Going ahead to step 8:
90 can be fit into 600 6 times, resulting in a remainder of 60.
The number 6 becomes the next digit in our result. 
Result so far: 4470.86
Deduct 540 from 600 and we're left with 60.
Since there are no more digits in the dividend, we add a zero to the remainder making it 600, and continue the process.

Let's proceed to step 9:
90 goes into 600 6 times with a remainder of 60.
Record the quotient 6 as the next digit in the result. 
Result so far: 4470.866
If we take 540 away from 600, we end up with 60.
Since there are no more digits in the dividend, we add a zero to the remainder making it 600, and continue the process.

After the division, we end up with 4470.866 and a remainder of 0.006.