My dd is in 2nd yr. of the Gr. 1-3 (Lower El) at her Montessori in Upstate NY. Every kid knew how to read coming into 1st grade but one, who is still not reading and has 'issues' (i.e.: she gets tutorial help every week). The expectation is that they can read, but not a requirement.
The school day starts with a look at the board - a write on wipe off board. There are 3 math questions they must answer (all children), but how they answer them is different for the different ages. Every day, unless there is something special happening, the children have to complete assignments -
The board says: Reading assignment, math skill cards, memorization (for appropriate aged math questions), math materials (for any kind of math), spelling, language (poetry, symbols, etc), and free time is used by the child to pursue their own interests in the classroom.
They also usually have a continual assignment, which changes from week/month to week/month. This month (mid apr - mid may her class is working on LIGHT). Ok, so they have these assignments to finish. If they don't? Well, They are given extra time to work on them (if they haven't finished most of the assignments) while the rest of the class goes to recess - they have to stay in for the first half of recess, and get to go out as soon as they catch up. Eventually they fall further and further behind in getting their work done and it's brought to your attention and you are called in for a conference (I haven't had to do this yet, so this is somewhat hearsay) and you decide together whether the classroom is 'working' for your child.
Every montessori is VERY different. Some classrooms even in the same school are very different. There are 3 1st - 3rd classes in dd's school. Her class seems more structured and less project oriented. There is another that is like the 'least fun' one, and another that is AMI, rather than AMS and very classroom hands on stuff, less free time to get your work done on your own.
Dd's class has great and key lessons, and they are used throughout the year to bring up specific topics that they then address using a few different methods. With light, they have projectors, use sunlight, made rainbows, and made shaddow puppet/theater. They have about 2 more weeks of light and then finish the year with something like air? Not sure. They've done water, soil, plants, rocks and energy already this year. Last year was similar but somewhat different.
I'm happy to answer specific questions, but as I said, every school is different. Some are super rigid about their enrollment policies, others are expanding their community and are less rigid. Others are more wadlorfian and artsy, others are very musical. Depends also on what kind of school - some are cooperative, some are run by a board etc. So look around Sphinx - the policies of the school will impact you more than what they teach in the classroom. In general, the Montessori schools do push reading more than math, but not all, and in general - but by no means always - they do expect 1st graders to be able to read step one ready to read books (a few words per page, 5-20pgs.). hth! Andy