Document u key.

1 files changed, 7 insertions, 1 deletions

diff --git a/hcalc.rst b/hcalc.rst
index 3bd0bef..4b3fba3 100644
--- a/hcalc.rst
+++ b/hcalc.rst
@@ -147,9 +147,15 @@ KEYBOARD
             *DEL* key: delete the rightmost digit.
 
 **C** **Escape**
-            *CLR* key: clears the number.
+            *CLR* key: clears the number and any pending operation.
+
+**u**
+            Clears the number, same as backspacing over it, but does not
+            clear any pending operation. There is no button in the UI for
+            this, so it can't be done with the mouse.
 
 **D** **H** **O** **B**
+            *DEC* *HEX* *OCT* *BIN* keys.
             Set the number base to decimal, hex, octal, or binary. The
             number currently displayed is converted into the new base.
             These are capital letters (hold down Shift).