Find the sum of all the multiples of 5 or 7 below 100

procs_multiples_5_and_7.rb

# create a Proc to use with a Block
multiples = Proc.new do |n|
  n % 5 == 0 || n % 7 == 0
end

# turn the Proc into a Block
array = (1..99).to_a.select(&multiples)

# sum the members of the array
array.inject{|sum,x| sum + x }

# reuse the Proc (remember Procs are Objects, Blocks are not, so they can be used over and over)
array2 = (1..999).to_a.select(&multiples)
array2.inject{|sum,x| sum + x }