Why multiple value to return calculator need?

Generally we hear that 100x returns we get on this stocks after t years. Then how to know what is simple or CAGR return, we need some calculations.

What is the multiple value to return calculator formula?

a= Multiple value
b= Time in years
c= Time in months
d= Time in days
Total time in years, y
Simple return in %, x
CAGR return in %, z
y= b+c/12+d/365
x= ((a-1)*100)
z= ((1+0.01*x)^^(1/y)-1)*100