42379899 ÷ 990 
Our goal is to divide 42379899 by 990.

Going ahead to step 1:
When dividing 4 by 990, we get 0 with a remainder of 4.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
The remainder is 4 after subtracting 0 from 4.
Grab the next digit (2) from the dividend, add it to 4, then carry on: 42 / 990

On to step 2:
The number 990 fits into 42 0 times, leaving a remainder of 42.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Deduct 0 from 42 and we're left with 42.
Grab the next digit (3) from the dividend, add it to 42, then carry on: 423 / 990

Step 3:
The number 990 fits into 423 0 times, leaving a remainder of 423.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
The remainder is 423 after subtracting 0 from 423.
Fetch the next digit (7) from the dividend, attach it to 423 and continue: 4237 / 990

On to step 4:
990 can be fit into 4237 4 times, resulting in a remainder of 277.
Write down 4 as next digit of the result. 
Result so far: 4.0
Subtract 3960 from 4237 to get 277.
Append the next digit (9) from the dividend to 277 and continue with: 2779 / 990

Going ahead to step 5:
If we divide 2779 by 990, we get 2 and a remainder of 799.
The number 2 becomes the next digit in our result. 
Result so far: 42.0
Subtracting 1980 from 2779 leaves us with 799.
Fetch the next digit (8) from the dividend, attach it to 799 and continue: 7998 / 990

On to step 6:
990 can be fit into 7998 8 times, resulting in a remainder of 78.
Use 8 as the next digit of our solution. 
Result so far: 428.0
The remainder is 78 after subtracting 7920 from 7998.
Include the next digit (9) from the dividend after 78, then repeat: 789 / 990

On to step 7:
The number 990 fits into 789 0 times, leaving a remainder of 789.
Put 0 as the next digit of the answer. 
Result so far: 4280.0
If we subtract 0 from 789, we get 789.
Grab the next digit (9) from the dividend, add it to 789, then carry on: 7899 / 990

On to step 8:
990 goes into 7899 7 times with a remainder of 969.
The number 7 becomes the next digit in our result. 
Result so far: 42807.0
Subtracting 6930 from 7899 leaves us with 969.
Since there are no more digits in the dividend, we add a zero to the remainder making it 9690, and continue the process.

On to step 9:
9690 divided by 990 is 9 with a remainder of 780.
Put 9 as the next digit of the answer. 
Result so far: 42807.9
Subtract 8910 from 9690 to get 780.
Since there are no more digits in the dividend, we add a zero to the remainder making it 7800, and continue the process.

Going ahead to step 10:
When dividing 7800 by 990, we get 7 with a remainder of 870.
Record the quotient 7 as the next digit in the result. 
Result so far: 42807.97
Subtract 6930 from 7800 to get 870.
Since there are no more digits in the dividend, we add a zero to the remainder making it 8700, and continue the process.

On to step 11:
The number 990 fits into 8700 8 times, leaving a remainder of 780.
Write down 8 as next digit of the result. 
Result so far: 42807.978
Subtract 7920 from 8700 to get 780.
Since there are no more digits in the dividend, we add a zero to the remainder making it 7800, and continue the process.

Step 12:
990 can be fit into 7800 7 times, resulting in a remainder of 870.
Record the quotient 7 as the next digit in the result. 
Result so far: 42807.9787
Subtract 6930 from 7800 to get 870.
Since there are no more digits in the dividend, we add a zero to the remainder making it 8700, and continue the process.

Step 13:
990 goes into 8700 8 times with a remainder of 780.
The next digit of our result is 8. 
Result so far: 42807.97878
If we subtract 7920 from 8700, we get 780.
Since there are no more digits in the dividend, we add a zero to the remainder making it 7800, and continue the process.

Going ahead to step 14:
The number 990 fits into 7800 7 times, leaving a remainder of 870.
Put 7 as the next digit of the answer. 
Result so far: 42807.978787
Deduct 6930 from 7800 and we're left with 870.
Since there are no more digits in the dividend, we add a zero to the remainder making it 8700, and continue the process.

Let's proceed to step 15:
If we divide 8700 by 990, we get 8 and a remainder of 780.
Write down 8 as next digit of the result. 
Result so far: 42807.9787878
Subtracting 7920 from 8700 leaves us with 780.
Since there are no more digits in the dividend, we add a zero to the remainder making it 7800, and continue the process.

Advancing to step 16:
When dividing 7800 by 990, we get 7 with a remainder of 870.
Write down 7 as next digit of the result. 
Result so far: 42807.97878787
Deduct 6930 from 7800 and we're left with 870.
Since there are no more digits in the dividend, we add a zero to the remainder making it 8700, and continue the process.

After the division, we end up with 42807.97878787 and a remainder of 8.7e-07.