how to pass multiple arguments in "include?" method in ruby

Question

#DATE IN MARCH 21(YEAR)Y/MONTH/D
reg="21MAR03"
invalid = false
if reg.length != 7
invalid = false
elsif reg[0..1].include?("21") && reg[2..4].include?("MAR")
#HOW CAN I INCLUDE 20 IN THE CODE
#LIKE include?("21","20") && reg[2..4].include?("MAR")
#ITS NOT WORKING
puts "valid"
invalid = true
end
if invalid==false
puts "invalid"
end

Answer 1

i would help you if i knew but do you know how to do the python for begniers search engine?

Answer 2

I have an idea how it works but don't know how to do exactly...