I'm liking the Casio FX-115ES PLUS rev 2 ($14.50), because it simplifies rationals and has LCM, GCD and factorization. For example, when you enter sin(60), it gives sqrt(3)/2, enter 1/(1+sqrt(3)) gives (sqrt(3)-1)/2 or enter sqrt(120) gives 2*sqrt(30).

https://www.amazon.com/Casio-fx-115ESPLS2-Advanced-Scientifi...

This is helpful for my kid's math class.

You wouldn't buy a textbook from Texas would you? So why buy a calculator from there when there is an option from Tokyo? :-)