We're dividing 84375910 by 858 
We want to figure out the number of times 84375910 can be divided by 858.

On to step 1:
When dividing 8 by 858, we get 0 with a remainder of 8.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtracting 0 from 8 leaves us with 8.
Bring next digit (4) of the dividend behind the 8 and repeat the process: 84 / 858

Moving on to step 2:
The number 858 fits into 84 0 times, leaving a remainder of 84.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we subtract 0 from 84, we get 84.
Take the next digit (3) from the dividend and append it to 84, then repeat: 843 / 858

Going ahead to step 3:
When dividing 843 by 858, we get 0 with a remainder of 843.
Write down 0 as next digit of the result. 
Result so far: 0.0
The remainder is 843 after subtracting 0 from 843.
Grab the next digit (7) from the dividend, add it to 843, then carry on: 8437 / 858

On to step 4:
If we divide 8437 by 858, we get 9 and a remainder of 715.
Write down 9 as next digit of the result. 
Result so far: 9.0
Subtract 7722 from 8437 to get 715.
Take the next digit (5) from the dividend and append it to 715, then repeat: 7155 / 858

Advancing to step 5:
858 can be fit into 7155 8 times, resulting in a remainder of 291.
Put 8 as the next digit of the answer. 
Result so far: 98.0
The remainder is 291 after subtracting 6864 from 7155.
Fetch the next digit (9) from the dividend, attach it to 291 and continue: 2919 / 858

Advancing to step 6:
858 can be fit into 2919 3 times, resulting in a remainder of 345.
Put 3 as the next digit of the answer. 
Result so far: 983.0
Subtracting 2574 from 2919 leaves us with 345.
Append the next digit (1) from the dividend to 345 and continue with: 3451 / 858

Going ahead to step 7:
The number 858 fits into 3451 4 times, leaving a remainder of 19.
Record the quotient 4 as the next digit in the result. 
Result so far: 9834.0
Deduct 3432 from 3451 and we're left with 19.
Grab the next digit (0) from the dividend, add it to 19, then carry on: 190 / 858

On to step 8:
When dividing 190 by 858, we get 0 with a remainder of 190.
Record the quotient 0 as the next digit in the result. 
Result so far: 98340.0
If we subtract 0 from 190, we get 190.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1900, and continue the process.

On to step 9:
858 can be fit into 1900 2 times, resulting in a remainder of 184.
Use 2 as the next digit of our solution. 
Result so far: 98340.2
Subtracting 1716 from 1900 leaves us with 184.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1840, and continue the process.

Step 10:
If we divide 1840 by 858, we get 2 and a remainder of 124.
The next digit of our result is 2. 
Result so far: 98340.22
Subtracting 1716 from 1840 leaves us with 124.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1240, and continue the process.

After the division, we end up with 98340.22 and a remainder of 0.124.