Ruby : Multiple way of multiplication

How to do multiplication in ruby using different concepts

1. Regular "*" operator

   3 * 3
   # => 9

2. Inject *

   [1, 2, 3].inject(:*)
   # => 6
   [1, 2, 3].reject(&:zero?).inject(:*) # if 0's

3. Reduce

   [1 ,2 ,3].reduce { |sum, x| sum + x }
   # => 6