Excercise 005

e005.erl

@@ -0,0 +1,25 @@
+% What is the smallest number divisible by each of the numbers 1 to 20?
+
+% 2520 is the smallest number that can be divided by each of the numbers from 1 to 10 without any remainder.
+% What is the smallest number that is evenly divisible by all of the numbers from 1 to 20?
+
+-module(e005).
+-export([
+    main/1
+]).
+
+divisible(N) ->
+    divisible(N, N, 1).
+divisible(_, C, X) when C == 1 ->
+    X;
+divisible(N, C, X) ->
+    if
+        X rem C == 0 ->
+            divisible(N, C - 1, X);
+        true ->
+            divisible(N, N, X + 1)
+    end.
+
+main(_) ->
+    io:format("Smallest number divisible by 1 to 10: ~w~n", [divisible(10)]),
+    io:format("Smallest number divisible by 1 to 10: ~w~n", [divisible(20)]).