diff --git a/README.md b/README.md
index 2606c1b..17f013a 100644
--- a/README.md
+++ b/README.md
@@ -280,6 +280,7 @@ Keybinding | Description
C-c g | Search in Google for the thing under point (or an interactive query).
C-c G | Search in GitHub for the thing under point (or an interactive query).
C-c y | Search in YouTube for the thing under point (or an interactive query).
+C-c U | Search in Duckduckgo for the thing under point (or an interactive query).
C-S-RET or Super-o | Insert an empty line above the current line and indent it properly.
S-RET or M-o | Insert an empty line and indent it properly (as in most IDEs).
C-S-up or M-S-up | Move the current line or region up.
@@ -290,14 +291,28 @@ Keybinding | Description
C-c u | Open URL in your default browser.
C-c e | Eval a bit of Emacs Lisp code and replace it with its result.
C-c s | Swap two active windows.
+C-c D | Delete current file and buffer.
C-c d | Duplicate the current line (or region).
C-c M-d | Duplicate and comment the current line (or region).
C-c r | Rename the currently visited file and buffer.
C-c t | Open a terminal emulator (`ansi-term`).
C-c k | Kill all open buffers except the one you're currently in.
+C-c TAB | Indent and copy region to clipboard
C-c h | Open Helm (available if you've enabled the `prelude-helm` module).
-C-c + | Increment integer at point.
-C-c - | Decrement integer at point.
+C-c I | Open user's init file.
+C-c S | Open shell's init file.
+C-h C-m | Display key bindings of current major mode and descriptions of every binding.
+C-c . + | Increment integer at point. Default is +1.
+C-c . - | Decrement integer at point. Default is -1.
+C-c . * | Multiply integer at point. Default is *2.
+C-c . / | Divide integer at point. Default is /2.
+C-c . \ | Modulo integer at point. Default is modulo 2.
+C-c . ^ | Power to the integer at point. Default is ^2.
+C-c . < | Left-shift integer at point. Default is 1 position to the left.
+C-c . > | Right-shift integer at point. Default is 1 position to the right.
+C-c . # | Convert integer at point to specified base. Default is 10.
+C-c . % | Replace integer at point with another specified integer.
+C-c . ' | Perform arithmetic operations on integer at point. User specifies the operator.
Super-r | Recent files
Super-x | Expand region
Super-j | Join lines
@@ -307,6 +322,9 @@ Keybinding | Description
Super-m f | Magit file log
Super-m b | Magit blame mode
+**Note**: For various arithmetic operations, the prefix `C-c .` only needs to be pressed once for the first operation.
+For subsequent operations, only the appropriate operations (i.e. `+`, `-`, `*`, `/`... needs to be pressed).
+
#### OSX modifier keys
Prelude does not mess by default with the standard mapping of `Command` (to `Super`) and `Option` (to `Meta`).
diff --git a/core/prelude-mode.el b/core/prelude-mode.el
index 0a172df..c09c2be 100644
--- a/core/prelude-mode.el
+++ b/core/prelude-mode.el
@@ -65,6 +65,7 @@
(define-key map (kbd "C-c h") 'helm-prelude)
(define-key map (kbd "C-c I") 'prelude-find-user-init-file)
(define-key map (kbd "C-c S") 'prelude-find-shell-init-file)
+ (define-key map 'help-command (kbd "C-m") 'discover-my-major)
;; make some use of the Super key
(define-key map [?\s-d] 'projectile-find-dir)
(define-key map [?\s-p] 'projectile-switch-project)
diff --git a/core/prelude-packages.el b/core/prelude-packages.el
index bdfb77a..a9360d3 100644
--- a/core/prelude-packages.el
+++ b/core/prelude-packages.el
@@ -49,6 +49,7 @@
anzu
browse-kill-ring
dash
+ discover-my-major
diff-hl
diminish
easy-kill