psh is not fancy with the types. The built-in types aim to give enough to get most simple things done.
Good ol' numbers.
Integers are numbers, Decimals are numbers, Fractions are numbers.
You can do maths on numbers.
"hello there"
Pretty straight forward, strings are strings.
Arrays (or lists) are one type of indexed collection, where the indexes are integers.
Indexes start at 0.
[1, 2, 3, 4, 5]