doc: add README.md

README.md

@@ -0,0 +1,21 @@
+# countdown-bash
+
+A generator and recursive solver for the Countdown Numbers game.
+
+Written in bash on [Termux](https://f-droid.org/en/packages/com.termux/) during a train ride. Not guaranteed to be fast, accurate, or provide the simplest solution.
+
+## Usage
+
+```bash
+$ ./countdown.sh 
+Target: 854
+Numbers: 10 50 4 9 7 1
+
+$ ./solve.sh 854 10 50 4 9 7 1
+won
+855 - 1 = 854
+57 x 15 = 855
+9 - -6 = 15
+50 + 7 = 57
+4 - 10 = -6
+```