Try to include mathematical jokes in your maths sessions as often as possible. Suggest your students make their own collections too. Make time to discuss why each joke is/is not funny. For example I really love this one shown below. You don’t need to know who Schrodinger actually was to appreciate this joke.
Schrodinger was a Nobel Prize-winning Austrian physicist who developed a number of fundamental results in quantum theory. Schrödinger’s cat is a his famous thought experiment, sometimes described as a paradox, devised by Schrödinger in 1935, though the idea originated from Albert Einstein. It questions whether a cat in an enclosed box is dead or alive, or could it actually be both, to illustrate the absurdity of the existing view of quantum mechanics. But we don’t need to know or understand any of this to get this joke.
This joke works in English but of course may not work well in other translations. It would make a lively discussion point with your Stage 3 students. Why not give it a go?