def foo
  (1..100).each do |num|
    if is_zero(num, 3) && is_zero(num, 5)
      p 'PingPong'
    elsif is_zero(num, 3)
      p 'Ping'
    elsif is_zero(num, 5)
      p 'Pong'
    else
      p num
    end
  end
end

def is_zero(num, denominator)
  (num%denominator) == 0
end

foo