You never know when you will need an extra hand. On an exam, it would come in pretty handy, right? But let’s leave puns aside for a second and talk business. If you can create the illusion that both hands are above your desk, you have one free hand to help with the answers for the test.
You can look through your notes and textbooks or even search for answers on your phone below your desk. Now, all you need is to find a sweater or a jumper and fill one of its sleeves to make it look like an arm. You can even use one of those fake hands they sell at costume shops.