Check if variable is number: Applescript

Question

How can I check if a variable is a number?

I\'m trying this:

set a to 5
if a is a number
display dialog \"Yes! It\'s a number!\"
end if

Answer 1

This is my solution:

on is_number(number_string)
    try
        set number_string to number_string as number
        return true
    on error
        return false
    end try
end is_number