You can make free phone calls within the US and to Canada with your Chromebook using the Hangouts app. You are able to call multiple numbers simultaneously, and also combine phone calls using the multi-way video chat,getting everyone on the line at one time.
- Press the search key.
- Choose Hangouts call.
- Choose Add Telephone and enter the phone number.
- Click the green Call button to be connected.
Find out more about phone calls using Hangouts here.