diff --git a/lib/mathlib.cpp b/lib/mathlib.cpp
index bc5c76b1d..ec40a37ba 100644
--- a/lib/mathlib.cpp
+++ b/lib/mathlib.cpp
@@ -397,13 +397,8 @@ bool MathLib::isBin(const std::string& s)
     return state == DIGITS;
 }
 
-bool MathLib::isInt(const std::string & s)
+bool MathLib::isDec(const std::string & s)
 {
-    // check for two known types: hexadecimal and octal
-    if (isHex(s) || isOct(s)) {
-        return true;
-    }
-
     enum {START, PLUSMINUS, DIGIT, SUFFIX} state = START;
     for (std::string::const_iterator it = s.begin(); it != s.end(); ++it) {
         switch (state) {
@@ -434,6 +429,11 @@ bool MathLib::isInt(const std::string & s)
     return state == DIGIT;
 }
 
+bool MathLib::isInt(const std::string & s)
+{
+    return isDec(s) || isHex(s) || isOct(s);
+}
+
 std::string MathLib::add(const std::string & first, const std::string & second)
 {
     if (MathLib::isInt(first) && MathLib::isInt(second)) {
diff --git a/lib/mathlib.h b/lib/mathlib.h
index 246baa05f..4e66f748c 100644
--- a/lib/mathlib.h
+++ b/lib/mathlib.h
@@ -47,6 +47,7 @@ public:
     static bool isFloat(const std::string &str);
     static bool isNegative(const std::string &str);
     static bool isPositive(const std::string &str);
+    static bool isDec(const std::string & str);
     static bool isHex(const std::string& str);
     static bool isOct(const std::string& str);
     static bool isBin(const std::string& str);