The number type represents real (double-precision floating-point) numbers. Lua has no integer type, as it does not need it.
local a = 3
local b = 2
local c = a + b
print(c) -- 3
local d = b - a
print(d) -- 1
local x = 1 * 2 * 5
print(x) -- 10
local y = (2 + 2) * 2
print(y) -- 8
print(10 / 2) -- 5
print(2 ^ 3) -- 8
print(5 % 2) -- 1