How to work out Surface area Instantly.

This trick allows you to work out the surface area almost instantly of ANY rectangular prism (or box). How do you work out the TSA (total surface area) of a box - watch this video and you'll be able to do it instantly!

To donate to the tecmath channel: https://paypal.me/tecmath?locale.x=en_AU

To support tecmath on Patreon: https://www.patreon.com/tecmath

To buy tecmath mechandise: https://teespring.com/stores/tecmath-store