We look at the division of 172742 by 90 
We want to figure out the number of times 172742 can be divided by 90.

Step 1:
When dividing 1 by 90, we get 0 with a remainder of 1.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we take 0 away from 1, we end up with 1.
Bring next digit (7) of the dividend behind the 1 and repeat the process: 17 / 90

On to step 2:
When dividing 17 by 90, we get 0 with a remainder of 17.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtract 0 from 17 to get 17.
Bring next digit (2) of the dividend behind the 17 and repeat the process: 172 / 90

Moving on to step 3:
When dividing 172 by 90, we get 1 with a remainder of 82.
Write down 1 as next digit of the result. 
Result so far: 1.0
If we take 90 away from 172, we end up with 82.
Fetch the next digit (7) from the dividend, attach it to 82 and continue: 827 / 90

Going ahead to step 4:
If we divide 827 by 90, we get 9 and a remainder of 17.
The number 9 becomes the next digit in our result. 
Result so far: 19.0
Subtract 810 from 827 to get 17.
Include the next digit (4) from the dividend after 17, then repeat: 174 / 90

Going ahead to step 5:
90 can be fit into 174 1 times, resulting in a remainder of 84.
Use 1 as the next digit of our solution. 
Result so far: 191.0
Subtract 90 from 174 to get 84.
Append the next digit (2) from the dividend to 84 and continue with: 842 / 90

On to step 6:
90 goes into 842 9 times with a remainder of 32.
The number 9 becomes the next digit in our result. 
Result so far: 1919.0
The remainder is 32 after subtracting 810 from 842.
Since there are no more digits in the dividend, we add a zero to the remainder making it 320, and continue the process.

Let's proceed to step 7:
90 can be fit into 320 3 times, resulting in a remainder of 50.
Put 3 as the next digit of the answer. 
Result so far: 1919.3
Subtract 270 from 320 to get 50.
Since there are no more digits in the dividend, we add a zero to the remainder making it 500, and continue the process.

On to step 8:
90 goes into 500 5 times with a remainder of 50.
Use 5 as the next digit of our solution. 
Result so far: 1919.35
Deduct 450 from 500 and we're left with 50.
Since there are no more digits in the dividend, we add a zero to the remainder making it 500, and continue the process.

Advancing to step 9:
When dividing 500 by 90, we get 5 with a remainder of 50.
Write down 5 as next digit of the result. 
Result so far: 1919.355
If we subtract 450 from 500, we get 50.
Since there are no more digits in the dividend, we add a zero to the remainder making it 500, and continue the process.

Our division results in 1919.355 with a remaining 0.005.