42291571 ÷ 870 
Our goal is to divide 42291571 by 870.

Step 1:
4 divided by 870 is 0 with a remainder of 4.
The next digit of our result is 0. 
Result so far: 0.0
Subtract 0 from 4 to get 4.
Append the next digit (2) from the dividend to 4 and continue with: 42 / 870

Going ahead to step 2:
42 divided by 870 is 0 with a remainder of 42.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtract 0 from 42 to get 42.
Take the next digit (2) from the dividend and append it to 42, then repeat: 422 / 870

On to step 3:
The number 870 fits into 422 0 times, leaving a remainder of 422.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we subtract 0 from 422, we get 422.
Include the next digit (9) from the dividend after 422, then repeat: 4229 / 870

Let's proceed to step 4:
870 goes into 4229 4 times with a remainder of 749.
Put 4 as the next digit of the answer. 
Result so far: 4.0
Deduct 3480 from 4229 and we're left with 749.
Grab the next digit (1) from the dividend, add it to 749, then carry on: 7491 / 870

Advancing to step 5:
7491 divided by 870 is 8 with a remainder of 531.
The number 8 becomes the next digit in our result. 
Result so far: 48.0
The remainder is 531 after subtracting 6960 from 7491.
Take the next digit (5) from the dividend and append it to 531, then repeat: 5315 / 870

Advancing to step 6:
The number 870 fits into 5315 6 times, leaving a remainder of 95.
Use 6 as the next digit of our solution. 
Result so far: 486.0
Deduct 5220 from 5315 and we're left with 95.
Bring next digit (7) of the dividend behind the 95 and repeat the process: 957 / 870

Step 7:
The number 870 fits into 957 1 times, leaving a remainder of 87.
Write down 1 as next digit of the result. 
Result so far: 4861.0
The remainder is 87 after subtracting 870 from 957.
Append the next digit (1) from the dividend to 87 and continue with: 871 / 870

Let's proceed to step 8:
The number 870 fits into 871 1 times, leaving a remainder of 1.
Record the quotient 1 as the next digit in the result. 
Result so far: 48611.0
If we take 870 away from 871, 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.

Going ahead to step 9:
When dividing 10 by 870, we get 0 with a remainder of 10.
The number 0 becomes the next digit in our result. 
Result so far: 48611.0
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.

On to step 10:
If we divide 100 by 870, we get 0 and a remainder of 100.
Write down 0 as next digit of the result. 
Result so far: 48611.0
Subtract 0 from 100 to get 100.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1000, and continue the process.

Our division results in 48611.0 with a remaining 0.1.