how to square number in ruby code example

Example: square every digit of a number ruby

number = 12345
number.to_s.chars.map { |num| num.to_i ** 2 }.join.to_i
# convert number to string (.to_s), convert string to array (.chars)
# .map each array element to the result of a block call. 
# .join array into string & convert back to integer.