Why return calculator by invested and current value need?

when we invested x amount in any stocks suppose after t years its turn around in 10x. Then what is simple and CAGR return and what is multiple value? For this we need some calculations.

What is the invested and current value to return calculator formula?

ai= Invested value
ac= Current 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
multiple value in times, mv
y= b+c/12+d/365
x= ((ac-ai)*100/ai)
mv= (ac/ai)
z= ((1+0.01*x)^^(1/y)-1)*100