<p>I’ve seen people write really light notes into their desk if they can’t remember an equation or name. No one can see it walking by, but the cheater can read it.</p>
<p>Slips of paper with notes on them in their sleeves or fist.</p>
<p>Keeping an open textbook on the floor next to them. [Usually in big lecture halls or when the professor leaves the room during the test. No idea why they do that.]</p>
<p>Switching calculators, definitely.</p>