How does the definition of percent you write fraction and decimal equivalents

A percent is a ratio of a number to 100. It is often used to communicate a relative amount. Per cent means "per 100".

12% means 12 out of 100 or 12/100 in fraction or 0.12 in decimal equivalents.

If a percentage is converted into a fraction without a whole number given, the denominator is always 100 and the fraction can be simplified by dividing both numerator and denominator by the common factor.
Example:
25% becomes 25 / 100. It can be simplified to 1 / 4.

If a percentage is converted into a decimal, based from the percent sign (%) move the decimal point to places to the left.

Example:
25% becomes  0.25  two places to the left from the % sign.
OR
125% becomes 1.25