I am teaching this personally at the moment. Unfortunately Texas Instruments have moved on from circa 1982 when I did pure and applied maths A levels. The school issued one is now fluro green and missing the square root button and the x to the power of y button. Perusal of the online manual informs me that the x to the y sign is now the little hat! The square root requires you to push 2 buttons then the number then enter then an arrow to the right. Holy cow. I found DHs calculator in his brief case and everything became much easier. His is 20 years old and entirely intuitive. Complete with square root and x to the power of y buttons.

I use little numbers quite often but they have names so you don't have to write the 10 to the power of a negative index. Things like micrograms and nanograms.

Binary gives me a headache but I guess anything is OK if you use it daily.

I am going to send the children to Khan academy and Plymouth uni and see if they are better than me. Lets hope so.