Donald Trump has announced 25% tariffs on Mexico and Canada. Here is how they would work and what such tariffs might mean.

President-elect Donald Trump's threat to impose tariffs on Canada, China and Mexico on the first day of his administration could dramatically raise prices for Americans on everything from cars to clothes to oil.

Put simply, tariffs are a tax on imports. Here's what Donald Trump did with them in his first term and how they impact the economy.