bandaid - those big square ones with padding. Place a little folded square of paper under that pad. Teachers don't want to rip off your bandaids. To make it look extra convincing, dribble a little dark red on the Band-Aid and let it dry before putting it then maybe place it on the inner elbow, like you just had a blood test/ needles for a realistic placement. If you are struggling to discreetly take it off put your hand up and say your hands bleeding on the test paper can I go to the nurses office for a new Band-Aid. Long fluttery sleeves might give you better cover for peeling it off if it's on your hands.
allowed liquids? Get a wide dark water bottle with a fully removable lid. Scribble on the inside of the bottle then fill the bottle with a dark drink? Cordial? just make sure the ink is safe ingestable and doesn't run when wet. Guzzle the drink start of test then peer inside.
this a bit common and teachers might look for it but most rectangular rubbers have a cardboard sleeve, scribble on the inside of that and redress the rubber.
wear watches? Write on the underside/skin side of the watch band. Start of the test take it off put it on the desk so it looks like your minding the time and observe your formulas.
I've totally not tried these...
allowed liquids? Get a wide dark water bottle with a fully removable lid. Scribble on the inside of the bottle then fill the bottle with a dark drink? Cordial? just make sure the ink is safe ingestable and doesn't run when wet. Guzzle the drink start of test then peer inside.
this a bit common and teachers might look for it but most rectangular rubbers have a cardboard sleeve, scribble on the inside of that and redress the rubber.
wear watches? Write on the underside/skin side of the watch band. Start of the test take it off put it on the desk so it looks like your minding the time and observe your formulas.
I've totally not tried these...