The teacher does not start the class.
The bell does not start the class.
You start the class.
Depending on the day of the week, they may also set a goal for the week, nominate a peer as a good citizen, and make a list of the multiples of a provided number.
Then they are expected to do any of the other work on their notebooks that is possible without teacher instruction. Much of the work is based in the areas of number sense and becomes progressively more difficult as we delve deeper into the school year.
With students coming into the room and getting class started by themselves, I can better greet them in the hallway every morning and get a feel for their attitudes for the day. I can also take care of those pesky housekeeping details such as roll call and lunch count.