How to round off a callback function

I need to round off my result to 2 decimal places


const conversion = (type, num) => {return type(num);} 
const cmToInches = (cm) => cm*2.54
const mlToOz = (ml) => ml*0.033814


conversion(ozToMl, 4)//should return 0.13 *Rounded to two decimal places*

It sould return 0.13 Rounded to two decimal places