10399962 ÷ 870 
We want to divide 10399962 by 870.

Step 1:
When dividing 1 by 870, we get 0 with a remainder of 1.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtract 0 from 1 to get 1.
Take the next digit (0) from the dividend and append it to 1, then repeat: 10 / 870

Going ahead to step 2:
The number 870 fits into 10 0 times, leaving a remainder of 10.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we subtract 0 from 10, we get 10.
Fetch the next digit (3) from the dividend, attach it to 10 and continue: 103 / 870

Moving on to step 3:
When dividing 103 by 870, we get 0 with a remainder of 103.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Deduct 0 from 103 and we're left with 103.
Grab the next digit (9) from the dividend, add it to 103, then carry on: 1039 / 870

On to step 4:
1039 divided by 870 is 1 with a remainder of 169.
The number 1 becomes the next digit in our result. 
Result so far: 1.0
The remainder is 169 after subtracting 870 from 1039.
Fetch the next digit (9) from the dividend, attach it to 169 and continue: 1699 / 870

On to step 5:
870 can be fit into 1699 1 times, resulting in a remainder of 829.
The next digit of our result is 1. 
Result so far: 11.0
Deduct 870 from 1699 and we're left with 829.
Bring next digit (9) of the dividend behind the 829 and repeat the process: 8299 / 870

Moving on to step 6:
870 can be fit into 8299 9 times, resulting in a remainder of 469.
The next digit of our result is 9. 
Result so far: 119.0
If we take 7830 away from 8299, we end up with 469.
Include the next digit (6) from the dividend after 469, then repeat: 4696 / 870

Let's proceed to step 7:
If we divide 4696 by 870, we get 5 and a remainder of 346.
Put 5 as the next digit of the answer. 
Result so far: 1195.0
Subtract 4350 from 4696 to get 346.
Include the next digit (2) from the dividend after 346, then repeat: 3462 / 870

Advancing to step 8:
3462 divided by 870 is 3 with a remainder of 852.
Use 3 as the next digit of our solution. 
Result so far: 11953.0
Subtract 2610 from 3462 to get 852.
Since there are no more digits in the dividend, we add a zero to the remainder making it 8520, and continue the process.

On to step 9:
The number 870 fits into 8520 9 times, leaving a remainder of 690.
Write down 9 as next digit of the result. 
Result so far: 11953.9
If we take 7830 away from 8520, we end up with 690.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6900, and continue the process.

Let's proceed to step 10:
When dividing 6900 by 870, we get 7 with a remainder of 810.
Put 7 as the next digit of the answer. 
Result so far: 11953.97
If we take 6090 away from 6900, we end up with 810.
Since there are no more digits in the dividend, we add a zero to the remainder making it 8100, and continue the process.

Step 11:
If we divide 8100 by 870, we get 9 and a remainder of 270.
The next digit of our result is 9. 
Result so far: 11953.979
If we take 7830 away from 8100, we end up with 270.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2700, and continue the process.

Advancing to step 12:
870 goes into 2700 3 times with a remainder of 90.
Use 3 as the next digit of our solution. 
Result so far: 11953.9793
Subtracting 2610 from 2700 leaves us with 90.
Since there are no more digits in the dividend, we add a zero to the remainder making it 900, and continue the process.

Let's proceed to step 13:
870 can be fit into 900 1 times, resulting in a remainder of 30.
Record the quotient 1 as the next digit in the result. 
Result so far: 11953.97931
If we take 870 away from 900, we end up with 30.
Since there are no more digits in the dividend, we add a zero to the remainder making it 300, and continue the process.

Advancing to step 14:
870 can be fit into 300 0 times, resulting in a remainder of 300.
Use 0 as the next digit of our solution. 
Result so far: 11953.97931
The remainder is 300 after subtracting 0 from 300.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3000, and continue the process.

On to step 15:
870 goes into 3000 3 times with a remainder of 390.
Write down 3 as next digit of the result. 
Result so far: 11953.9793103
Subtract 2610 from 3000 to get 390.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3900, and continue the process.

Moving on to step 16:
870 goes into 3900 4 times with a remainder of 420.
The number 4 becomes the next digit in our result. 
Result so far: 11953.97931034
Subtracting 3480 from 3900 leaves us with 420.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4200, and continue the process.

The quotient of the division is 11953.97931034, and the remainder is 4.2e-07.