Let's divide 42125843 by 991
We're looking to find how many times 991 goes into 42125843.

Moving on to step 1:
The number 991 fits into 4 0 times, leaving a remainder of 4.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Deduct 0 from 4 and we're left with 4.
Bring next digit (2) of the dividend behind the 4 and repeat the process: 42 / 991

On to step 2:
The number 991 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
The remainder is 42 after subtracting 0 from 42.
Take the next digit (1) from the dividend and append it to 42, then repeat: 421 / 991

Going ahead to step 3:
When dividing 421 by 991, we get 0 with a remainder of 421.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we subtract 0 from 421, we get 421.
Include the next digit (2) from the dividend after 421, then repeat: 4212 / 991

On to step 4:
4212 divided by 991 is 4 with a remainder of 248.
Use 4 as the next digit of our solution. 
Result so far: 4.0
Subtract 3964 from 4212 to get 248.
Grab the next digit (5) from the dividend, add it to 248, then carry on: 2485 / 991

Advancing to step 5:
When dividing 2485 by 991, we get 2 with a remainder of 503.
Put 2 as the next digit of the answer. 
Result so far: 42.0
Subtract 1982 from 2485 to get 503.
Grab the next digit (8) from the dividend, add it to 503, then carry on: 5038 / 991

Step 6:
5038 divided by 991 is 5 with a remainder of 83.
Record the quotient 5 as the next digit in the result. 
Result so far: 425.0
Deduct 4955 from 5038 and we're left with 83.
Bring next digit (4) of the dividend behind the 83 and repeat the process: 834 / 991

Advancing to step 7:
991 goes into 834 0 times with a remainder of 834.
Put 0 as the next digit of the answer. 
Result so far: 4250.0
Subtracting 0 from 834 leaves us with 834.
Take the next digit (3) from the dividend and append it to 834, then repeat: 8343 / 991

Let's proceed to step 8:
The number 991 fits into 8343 8 times, leaving a remainder of 415.
Put 8 as the next digit of the answer. 
Result so far: 42508.0
Deduct 7928 from 8343 and we're left with 415.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4150, and continue the process.

Going ahead to step 9:
991 goes into 4150 4 times with a remainder of 186.
Put 4 as the next digit of the answer. 
Result so far: 42508.4
Deduct 3964 from 4150 and we're left with 186.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1860, and continue the process.

On to step 10:
1860 divided by 991 is 1 with a remainder of 869.
Use 1 as the next digit of our solution. 
Result so far: 42508.41
Subtracting 991 from 1860 leaves us with 869.
Since there are no more digits in the dividend, we add a zero to the remainder making it 8690, and continue the process.

Advancing to step 11:
The number 991 fits into 8690 8 times, leaving a remainder of 762.
Record the quotient 8 as the next digit in the result. 
Result so far: 42508.418
Subtracting 7928 from 8690 leaves us with 762.
Since there are no more digits in the dividend, we add a zero to the remainder making it 7620, and continue the process.

Advancing to step 12:
When dividing 7620 by 991, we get 7 with a remainder of 683.
The next digit of our result is 7. 
Result so far: 42508.4187
If we take 6937 away from 7620, we end up with 683.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6830, and continue the process.

Let's proceed to step 13:
6830 divided by 991 is 6 with a remainder of 884.
Record the quotient 6 as the next digit in the result. 
Result so far: 42508.41876
Deduct 5946 from 6830 and we're left with 884.
Since there are no more digits in the dividend, we add a zero to the remainder making it 8840, and continue the process.

On to step 14:
8840 divided by 991 is 8 with a remainder of 912.
Use 8 as the next digit of our solution. 
Result so far: 42508.418768
Subtracting 7928 from 8840 leaves us with 912.
Since there are no more digits in the dividend, we add a zero to the remainder making it 9120, and continue the process.

On to step 15:
When dividing 9120 by 991, we get 9 with a remainder of 201.
The next digit of our result is 9. 
Result so far: 42508.4187689
Subtract 8919 from 9120 to get 201.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2010, and continue the process.

Moving on to step 16:
991 goes into 2010 2 times with a remainder of 28.
Write down 2 as next digit of the result. 
Result so far: 42508.41876892
If we subtract 1982 from 2010, we get 28.
Since there are no more digits in the dividend, we add a zero to the remainder making it 280, and continue the process.

The final outcome is 42508.41876892, with a leftover of 2.8e-08.