diff --git a/src/rime/gear/script_translator.cc b/src/rime/gear/script_translator.cc
index 250616593e..e220aed9cf 100644
--- a/src/rime/gear/script_translator.cc
+++ b/src/rime/gear/script_translator.cc
@@ -488,9 +488,9 @@ void ScriptTranslation::PrepareCandidate() {
                        start_,
                        start_ + user_phrase_code_length,
                        entry);
-    cand->set_quality(exp(entry->weight) +
-                      translator_->initial_quality() +
-                      (IsNormalSpelling() ? 0.5 : -0.5));
+    cand->set_quality(std::exp(entry->weight) +
+                     translator_->initial_quality() +
+                     (IsNormalSpelling() ? 0.5 : -0.5));
   }
   else if (phrase_code_length > 0) {
     DictEntryIterator& iter = phrase_iter_->second;
@@ -502,9 +502,9 @@ void ScriptTranslation::PrepareCandidate() {
                        start_,
                        start_ + phrase_code_length,
                        entry);
-    cand->set_quality(exp(entry->weight) +
-                      translator_->initial_quality() +
-                      (IsNormalSpelling() ? 0 : -1));
+    cand->set_quality(std::exp(entry->weight) +
+                     translator_->initial_quality() +
+                     (IsNormalSpelling() ? 0 : -1));
   }
   candidate_ = cand;
 }
diff --git a/src/rime/gear/table_translator.cc b/src/rime/gear/table_translator.cc
index c95e5e24ba..97cfc96e52 100644
--- a/src/rime/gear/table_translator.cc
+++ b/src/rime/gear/table_translator.cc
@@ -81,10 +81,10 @@ an<Candidate> TableTranslation::Peek() {
   if (phrase) {
     phrase->set_comment(comment);
     phrase->set_preedit(preedit_);
-    phrase->set_quality(exp(e->weight) +
-                        options_->initial_quality() +
-                        (incomplete ? -1 : 0) +
-                        (is_user_phrase ? 0.5 : 0));
+    phrase->set_quality(std::exp(e->weight) +
+                       options_->initial_quality() +
+                       (incomplete ? -1 : 0) +
+                       (is_user_phrase ? 0.5 : 0));
   }
   return phrase;
 }