75159561 ÷ 870 
Let's see how many times 870 fits into 75159561.

On to step 1:
If we divide 7 by 870, we get 0 and a remainder of 7.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
The remainder is 7 after subtracting 0 from 7.
Append the next digit (5) from the dividend to 7 and continue with: 75 / 870

Advancing to step 2:
If we divide 75 by 870, we get 0 and a remainder of 75.
The next digit of our result is 0. 
Result so far: 0.0
Subtract 0 from 75 to get 75.
Append the next digit (1) from the dividend to 75 and continue with: 751 / 870

Going ahead to step 3:
When dividing 751 by 870, we get 0 with a remainder of 751.
The next digit of our result is 0. 
Result so far: 0.0
Subtracting 0 from 751 leaves us with 751.
Take the next digit (5) from the dividend and append it to 751, then repeat: 7515 / 870

Moving on to step 4:
When dividing 7515 by 870, we get 8 with a remainder of 555.
Write down 8 as next digit of the result. 
Result so far: 8.0
Subtracting 6960 from 7515 leaves us with 555.
Bring next digit (9) of the dividend behind the 555 and repeat the process: 5559 / 870

Moving on to step 5:
The number 870 fits into 5559 6 times, leaving a remainder of 339.
Put 6 as the next digit of the answer. 
Result so far: 86.0
Deduct 5220 from 5559 and we're left with 339.
Fetch the next digit (5) from the dividend, attach it to 339 and continue: 3395 / 870

Going ahead to step 6:
3395 divided by 870 is 3 with a remainder of 785.
The next digit of our result is 3. 
Result so far: 863.0
If we take 2610 away from 3395, we end up with 785.
Grab the next digit (6) from the dividend, add it to 785, then carry on: 7856 / 870

Step 7:
If we divide 7856 by 870, we get 9 and a remainder of 26.
The next digit of our result is 9. 
Result so far: 8639.0
Subtracting 7830 from 7856 leaves us with 26.
Take the next digit (1) from the dividend and append it to 26, then repeat: 261 / 870

On to step 8:
When dividing 261 by 870, we get 0 with a remainder of 261.
The number 0 becomes the next digit in our result. 
Result so far: 86390.0
Deduct 0 from 261 and we're left with 261.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2610, and continue the process.

On to step 9:
If we divide 2610 by 870, we get 3 and a remainder of 0.
Use 3 as the next digit of our solution. 
Result so far: 86390.3
The remainder is 0 after subtracting 2610 from 2610.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

On to step 10:
When dividing 0 by 870, we get 0 with a remainder of 0.
Use 0 as the next digit of our solution. 
Result so far: 86390.3
Subtracting 0 from 0 leaves us with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Let's proceed to step 11:
The number 870 fits into 0 0 times, leaving a remainder of 0.
Write down 0 as next digit of the result. 
Result so far: 86390.3
Subtract 0 from 0 to get 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

The final outcome is 86390.3, with a leftover of 0.0.