diff --git a/Base/res/html/misc/calc.html b/Base/res/html/misc/calc.html
index 5c8e5a5521..1141afdb3c 100644
--- a/Base/res/html/misc/calc.html
+++ b/Base/res/html/misc/calc.html
@@ -39,6 +39,11 @@
         <div class="box" style="width: calc(50% + 60px);"></div>
     </div>
 
+    <p>calc(50% - 60px)</p>
+    <div class="container">
+        <div class="box" style="width: calc(50% - 60px);"></div>
+    </div>
+
     <p>calc(50% + -60px)</p>
     <div class="container">
         <div class="box" style="width: calc(50% + -60px);"></div>