i'm supposed to come up with different questions for 11-12 year olds, 13-14 year olds, and 17 year olds. the topic is the triangular number sequence.

any ideas for them?

Hmm for the 11-12 year olds you should do stuff with equations, wait no correction for the 14 year olds. I cant think of any at the moment, but when I do, I will get to you on here.