diff --git a/lib/valueflow.cpp b/lib/valueflow.cpp
index 359974564..d77ce27d5 100644
--- a/lib/valueflow.cpp
+++ b/lib/valueflow.cpp
@@ -378,10 +378,14 @@ static void setTokenValue(Token* tok, const ValueFlow::Value &value)
 
     // Calculations..
     else if (parent->isArithmeticalOp() && parent->astOperand1() && parent->astOperand2()) {
+        const bool known = ((parent->astOperand1()->values.size() == 1U &&
+                             parent->astOperand1()->values.front().valueKind == ValueFlow::Value::ValueKind::Known) ||
+                            (parent->astOperand2()->values.size() == 1U &&
+                             parent->astOperand2()->values.front().valueKind == ValueFlow::Value::ValueKind::Known));
         std::list<ValueFlow::Value>::const_iterator value1, value2;
         for (value1 = parent->astOperand1()->values.begin(); value1 != parent->astOperand1()->values.end(); ++value1) {
             for (value2 = parent->astOperand2()->values.begin(); value2 != parent->astOperand2()->values.end(); ++value2) {
-                if (value1->varId == 0U || value2->varId == 0U ||
+                if (known || value1->varId == 0U || value2->varId == 0U ||
                     (value1->varId == value2->varId && value1->varvalue == value2->varvalue)) {
                     ValueFlow::Value result(0);
                     result.condition = value1->condition ? value1->condition : value2->condition;
diff --git a/test/testvalueflow.cpp b/test/testvalueflow.cpp
index ece65b843..99994cb88 100644
--- a/test/testvalueflow.cpp
+++ b/test/testvalueflow.cpp
@@ -218,12 +218,7 @@ private:
 
     void valueFlowCalculations() {
         const char *code;
-        /*
-                code  = "void f() {\n"
-                        "    x = 123+456;\n"
-                        "}";
-                ASSERT_EQUALS(579, valueOfTok(code, "+").intvalue);
-        */
+
         code  = "void f(int x) {\n"
                 "    a = x+456;\n"
                 "    if (x==123) {}"
@@ -252,6 +247,14 @@ private:
         ASSERT_EQUALS(4, values.front().intvalue);
         ASSERT_EQUALS(16, values.back().intvalue);
 
+        // addition of different variables with known values
+        code = "int f(int x) {\n"
+               "  int a = 1;\n"
+               "  while (x!=3) { x+=a; }\n"
+               "  return x/a;\n"
+               "}\n";
+        ASSERT_EQUALS(3, valueOfTok(code, "/").intvalue);
+
         // ? :
         code = "x = y ? 2 : 3;\n";
         values = tokenValues(code,"?");