MakeMaths.rb

=begin

Given two numbers and an arithmetic operator (the name of it, as a string),
return the result of the two numbers having that operator used on them.

a and b will both be positive integers, and a will always be the first number
in the operation, and b always the second.

The four operators are "add", "subtract", "divide", "multiply".

A few examples:

arithmetic(5, 2, "add") should return 7

arithmetic(5, 2, "subtract") should return 3

arithmetic(5, 2, "multiply") should return 10

arithmetic(5, 2, "divide") should return 2.5

=end

# My Solution
def arithmetic(a, b, operator)
  case operator
    when "add" ; a + b
    when "subtract" ; a - b
    when "multiply" ; a * b
    when "divide" ; a / b
  end
end

# Better Solution
def arithmetic(a, b, operator)
 ar={"add"=>a+b,"subtract"=>a-b,"multiply"=>a*b,"divide"=>a.div(b)}
 ar[operator]
end