Trick: Multiplying double digit numbers

To keep my brain limber, I sometimes think of two random double-digit numbers and try to multiply them by each other as fast as I can. Weird, I know. Oh well.

• First, multiply 1 x 4 and bring it straight down (4)
• Then, cross multiply (3×4 and 1×2) and add each of them up (12 + 2), save whatever is in the 10′s place (1), and bring what is in the 1′s place down (4)
• Lastly, Multiply straight up and down (3×2) and add what was leftover (1)

That’s it.