1) Is there a typical class structure/schedule you use for the 90 min? Warm-up, close, etc?
My favorite thing about having a long block is that there is actually time to have all the aspects of a class that we hear we're supposed to include but just don't fit in a 45 minute period. In my class there's some sort of do now on the board as students walk in (for PreCalc it's the daily SET, for Algebra 1 it varies). I check the homework while they work, then we discuss a few problems from the homework. Maybe there's a three question quiz. Then students get to do some work, with interspersed discussion. And we finish with time to reflect on the class and assign homework!
2) Is retention a bigger problem? If so, what, if anything, do you do to spiral/review b/w class days?
It is hard to be on an alternating block because if you have class on Friday you don't see them again until Tuesday. For my honors precalc kids I expect them to be able to look back at their notes and recall what we were doing last class. They do have homework but it's fairly traditional, a few problems to continue practicing what we learned today. At the beginning of my algebra classes I try to remind students where we left off to build in the connections more visibly. We also tried to have spiraling homework last year and are hoping to continue that throughout this year.
3) Same question as 2 but for absences. I'm worried about students missing Thurs & not having math for a week
Absences are tough. Missing 90 minutes of class is a lot! We have a system where each subject has one day a week that the teachers are available after school and so we all tell students that they should come after school if they are absent. However, they don't often follow through. I have a smart board in my classroom so I can save all the notes as a pdf and post them on my website. Some of my precalc students make good use of the website, and it's also helpful for me to be able to reference things when students do come after school. Otherwise it's just like any other class absence, have a place for students to get handouts they missed, encourage them to get notes from someone and make up any owed assignments!
4) What do you love about the 90 min & what do you think are best ways to make full use of the long period?
The best thing is how few transitions students have throughout the day. It's hard for students to go from gym to science to math and switch modes. Our block schedule means that transition only happens three times a day. Once they're in class the pencils are out, they found some paper, and they're yours for a solid chunk of time. You have time to do stations or projects or investigations. But remember, you don't have twice as much time as before just because class periods are twice as long! You have two class periods in one, so you need to make sure you're hitting enough content and not spending all your time making pretty posters.
5) Any suggestions for breaking up the time & keeping student engagement/energy high throughout?
It is a really long time to just let them work without any structures. You have time to do all the aspects of class - hook, formative assessment, discovery, consolidate, review - so do so! Activities that get kids up and moving are good from time to time, mostly I find a simple system for kids to self regulate breaks to the water fountain and bathroom is key. Even on days where I do want students to work through a longer problem set I have implemented structures to break up the time. I'll set a timer for 7-10 minutes and then use a random number generator to call on a student to share their work on a problem everyone has had a chance to work on. Repeat until you're done with the problem set or ready to close class!