The federal election campaign is officially underway and among the first promises of the leading parties is an income tax cut. Andrew Chang breaks down the math behind the two plans to explain how much you would save, and why experts are skeptical about how either would pay for it. »»» Subscribe to CBC News to watch more videos: http://bit.ly/1RreYWS Connect with CBC News Online: For breaking news, video, audio and in-depth coverage: http://bit.ly/1Z0m6iX Follow CBC News on TikTok: https://bit.