Your guides to the weird side of the web explain the Magic 13 mathematical card trick.

Add Yahoo as a preferred source to see more of our stories on Google. Math shouldn’t be harder than finding the last matching sock in your laundry. These clever shortcuts convert head-scratching ...

Maggi Ajjayya, Kottur’s “Computer Man,” amazes social media with lightning-fast mental math. Despite only studying till 8th grade and surviving by begging, his calculation tricks have gone viral.