2 files changed, 2 insertions, 1 deletions
diff --git a/hcalc.rst b/hcalc.rst
index 0dd2235..b54e6ed 100644
--- a/hcalc.rst
+++ b/hcalc.rst
@@ -126,7 +126,7 @@ KEYBOARD
             Decimal point. Only works in decimal mode (base 10); other bases
             are integer-only.
 
-**_**
+**_** **i**
             Invert sign. The *+/-* key.
 
 **=** **Enter**
diff --git a/input.c b/input.c
index c46a92a..92824e3 100644
--- a/input.c
+++ b/input.c
@@ -306,6 +306,7 @@ key(char c)
     break;
 
   case '_': /* The +/- key */
+  case 'i':
     if (making_number)
     {
       if (input_buf[0] == '-')