Ruby task- Help my explain why I receive output in this =7

Question

What is the output of this code?
*a,b= [1,2,3,4]
Puts a[b-2] +b

# output= 7
I just wh ant understand why?

Answer 1

Андрей Рыбаков

a is a list
And a[2] means value at index 2 which is 3
As index start from 0..
a[0]=1
a[1]=2
a[2]=3

Answer 2

Yes. Indira's answer is an extremely clear answer.

Answer 3

ok, But how did this expression turn into this
a[2] --->3?
a=1+2+3=6
6[2]--->6/2?