Finding lowest number to multiply a fraction and get a whole

I am trying to find the multiplier for a fraction that will let me get a whole number.

So trying to solve $c=a\times b$

Where $a$ is a number like $1.6$ or $0.7$ or $5.24$

Where $b$ is the lowest number that $a$ can be multiplied by to make $c$ a whole number.

The use case is in a game I am programming the currency is only in whole numbers of a single denomination (single gold coins) if the player wants to sell a quantity of items that are worth a fractional value like $1.6$, how many must they sell so they can receive a whole number without throwing out the fractions.

I am trying to find the multiplier for a fraction that will let me get a whole number.

So trying to solve $c=a\times b$

Where $a$ is a number like $1.6$ or $0.7$ or $5.24$

Where $b$ is the lowest number that $a$ can be multiplied by to make $c$ a whole number.

The use case is in a game I am programming the currency is only in whole numbers of a single denomination (single gold coins) if the player wants to sell a quantity of items that are worth a fractional value like $1.6$, how many must they sell so they can receive a whole number without throwing out the fractions.