How do you change $1.66$ into fraction?

Hint: In order to calculate the fraction equivalent of any decimal number, first we calculate the number of digits after the decimal point and divide the number with 10 raised to power that number and remove the decimal point. After simplifying more further, we will obtain our required answer.

Complete step by step answer:
We are given a decimal number $1.66$.
So in order to change any decimal number in the fraction equivalent, divide the number with 10 raised to the power no of digits written after the decimal point and remove the decimal point in the end.
Here in our decimal number $1.66$, no of digits after decimal point is equal to 2, so dividing the number with ${10^2}$, we get
$
   = 1.66 \\
   = \dfrac{{166}}{{{{10}^2}}} \\
   = \dfrac{{166}}{{100}} \\
 $
Simplifying the fraction, we get
$ = \dfrac{{83}}{{50}}$
Therefore, the fraction equivalent of the decimal number $1.66$ is $\dfrac{{83}}{{50}}$.

Note: 1. Don’t forget to remove the decimal point in the end .
2. To calculate fraction from the percentage , divide the given percentage value by 100
For example : We have to write $70\% $into fraction
$
   = \dfrac{{70}}{{100}} \\
   = \dfrac{7}{{10}} \\
 $
Or $ = 0.7$
3. If you want to Increase a Number by y %:
Example:
On the off chance that a number is expanded by \[10{\text{ }}\% \], at that point it becomes 1.1 times of itself.
On the off chance that a number is expanded by 30 %, at that point it becomes 1.3 times of itself.
4. If you want to Decrease a Number by y %:
Example: On the off chance that a number is diminished by 10 %, at that point it becomes 0.90 times of itself. On the off chance that a number is diminished by 30 %, at that point it becomes 0.70 times of itself.