7991638 divided by 870 
Let's see how many times 870 fits into 7991638.

Step 1:
7 divided by 870 is 0 with a remainder of 7.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtracting 0 from 7 leaves us with 7.
Take the next digit (9) from the dividend and append it to 7, then repeat: 79 / 870

Going ahead to step 2:
When dividing 79 by 870, we get 0 with a remainder of 79.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 79 and we're left with 79.
Bring next digit (9) of the dividend behind the 79 and repeat the process: 799 / 870

On to step 3:
799 divided by 870 is 0 with a remainder of 799.
The next digit of our result is 0. 
Result so far: 0.0
If we take 0 away from 799, we end up with 799.
Bring next digit (1) of the dividend behind the 799 and repeat the process: 7991 / 870

Advancing to step 4:
870 goes into 7991 9 times with a remainder of 161.
Put 9 as the next digit of the answer. 
Result so far: 9.0
Subtracting 7830 from 7991 leaves us with 161.
Append the next digit (6) from the dividend to 161 and continue with: 1616 / 870

Step 5:
The number 870 fits into 1616 1 times, leaving a remainder of 746.
Write down 1 as next digit of the result. 
Result so far: 91.0
Deduct 870 from 1616 and we're left with 746.
Grab the next digit (3) from the dividend, add it to 746, then carry on: 7463 / 870

Step 6:
7463 divided by 870 is 8 with a remainder of 503.
The number 8 becomes the next digit in our result. 
Result so far: 918.0
The remainder is 503 after subtracting 6960 from 7463.
Take the next digit (8) from the dividend and append it to 503, then repeat: 5038 / 870

On to step 7:
When dividing 5038 by 870, we get 5 with a remainder of 688.
The next digit of our result is 5. 
Result so far: 9185.0
If we subtract 4350 from 5038, we get 688.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6880, and continue the process.

Advancing to step 8:
When dividing 6880 by 870, we get 7 with a remainder of 790.
The next digit of our result is 7. 
Result so far: 9185.7
The remainder is 790 after subtracting 6090 from 6880.
Since there are no more digits in the dividend, we add a zero to the remainder making it 7900, and continue the process.

Advancing to step 9:
7900 divided by 870 is 9 with a remainder of 70.
Use 9 as the next digit of our solution. 
Result so far: 9185.79
The remainder is 70 after subtracting 7830 from 7900.
Since there are no more digits in the dividend, we add a zero to the remainder making it 700, and continue the process.

On to step 10:
700 divided by 870 is 0 with a remainder of 700.
The number 0 becomes the next digit in our result. 
Result so far: 9185.79
If we take 0 away from 700, we end up with 700.
Since there are no more digits in the dividend, we add a zero to the remainder making it 7000, and continue the process.

Step 11:
When dividing 7000 by 870, we get 8 with a remainder of 40.
Write down 8 as next digit of the result. 
Result so far: 9185.7908
Subtract 6960 from 7000 to get 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 400, and continue the process.

Going ahead to step 12:
The number 870 fits into 400 0 times, leaving a remainder of 400.
Write down 0 as next digit of the result. 
Result so far: 9185.7908
If we subtract 0 from 400, we get 400.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4000, and continue the process.

Let's proceed to step 13:
If we divide 4000 by 870, we get 4 and a remainder of 520.
The next digit of our result is 4. 
Result so far: 9185.790804
Subtract 3480 from 4000 to get 520.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5200, and continue the process.

Advancing to step 14:
When dividing 5200 by 870, we get 5 with a remainder of 850.
The number 5 becomes the next digit in our result. 
Result so far: 9185.7908045
Subtract 4350 from 5200 to get 850.
Since there are no more digits in the dividend, we add a zero to the remainder making it 8500, and continue the process.

Let's proceed to step 15:
8500 divided by 870 is 9 with a remainder of 670.
Record the quotient 9 as the next digit in the result. 
Result so far: 9185.79080459
Deduct 7830 from 8500 and we're left with 670.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6700, and continue the process.

The final result is 9185.79080459 with a remainder of 6.7e-07.