diff --git a/src/arithmetic.py b/src/arithmetic.py
index 037d67a..2493d65 100644
--- a/src/arithmetic.py
+++ b/src/arithmetic.py
@@ -21,7 +21,7 @@ def t_NUMBER(t):
 
 def t_EXP(t):
     r'\*\*'
-    pass
+    return t
 
 lexer = ply.lex.lex()