Add multilingual language and systems learning tracks

en/ruby-practice-20261101/lesson-3/main.rb

@@ -0,0 +1,6 @@
+def remaining(total, done)
+  [0, total - done].max
+end
+
+raise "Test failed" unless remaining(4,1) == 3 && remaining(4,4) == 0 && remaining(4,5) == 0 && remaining(0,0) == 0
+puts "Passed"