Katie has a PhD in maths, specializing in the intersection of dynamical systems and number theory. She reports on topics from maths and history to society and animals. Katie has a PhD in maths, ...

Stay on top of what’s happening in the Bay Area with essential Bay Area news stories, sent to your inbox every weekday. The Bay Bay Area-raised host Ericka Cruz Guevarra brings you context and ...

Let the Worst Witch's Mildred Hubble get your class up and moving with this song and movement routine about calculating percentages. Download the lyric sheet so ...

Percentages come in handy in understanding anything from sports to news and of course, shopping. However, around 80% of the population struggle with understanding percentages. Animator Josh Kurz ...

SHOP ASSISTANT:That looks so good on you. UNKNOWN WOMAN #2:Oh, thanks. Is that the sale price? SHOP ASSISTANT:No, there's 20% discount on the marked price of all these dresses. UNKNOWN WOMAN #2:Great!

Fast Percentage calculations in mind using Mental Maths: Calculate almost any percentage in your mind. Simple tricks to calculate percentages like 10%, 20%, 75% and more mentally. This is useful for ...