Most Common Shortcuts

Ctrl + S – Save
Ctrl + A – Select all items on the page or the active text box
Ctrl + C – Copy
Ctrl + V – Paste
Ctrl + X – Cut
Ctrl + P – Opens the Print dialog box
Ctrl + Z – Undo last change
F5 – View the complete slide show
Shift + F5 – View the slide show from the current slide forward.
Shift + Ctrl + Home – Selects all text from the cursor to the start of the active text box
Shift + Ctrl + End – Selects all text from the cursor to the end of the active text box
Spacebar or Click the mouse – Move to next slide or next animation
S – Stop the show. Press S again to restart the show
Esc- End the slide show

For who didn’t understand what is shortcuts?
For a example :

Ctrl + S – Save
It means you press Ctrl button and S both, then powerpoint will save your file.