This whole book talks about the impact of Daily Number Sense Routines in your classroom. These routines are low floor/high ceiling activities that take maybe 5-10 minutes of your daily block of time, and pack a HUGE bang for your buck!
I am sure you have seen some of the routines before...such as Which One Doesn't Belong or Same and Different. My students LOVE these activities because they are meant to be successful for EVERYONE.
Take for example this Which One doesn't belong:
Students get some think time to decide which of these numbers DOES NOT belong with the others. Students can enter this activity with an answer as simple as "5 because it's the only one digit number". Another student can say that 5 doesn't belong because it's the only prime number-which increases the complexity of their answer. However, when you have these discussions as a class, students are being exposed to math vocabulary and number sense and fluency.
If you also look at the Standards of Mathematical Practice, these Number Sense Routines fit ALL 8 of them with a 5-10 minute block of you time.
