For those of you who take sandcastle building very seriously, listen up: engineers now say you can trust a very simple equation to calculate the force required to push a shovel -- and any other ...

Get out your timer and number two pencil to see if your arithmetic skills are still sharp.

Add Yahoo as a preferred source to see more of our stories on Google. It seemed that many were quick to figure out the equation, while others definitley struggled. You’re never too old to learn ...