Maths in focus teaches the basics, you need to learn how to walk before you can run.
i used maths in focus for hsc, wasnt that bad, i did do alot of questions though from like past paper books, and practice exam books. However, maths in focus is a little shit on some topics, and misses out some content completely, so watch out lol. I remember sketching derivative/integral graphs wasnt in there. and yeh just the way they as ask are not exam like ( especially in topics such as circles )
The teachers are there to teach theory, you teach yourself exam questions.