Teacher Choice activities for Guided Math Workshop are literally just that: teacher choice.
This is a great way to incorporate a Tech station (computer, calculator skills) in smaller groups (logging in only a few students instead of a whole class); or Mashup Math puzzles; or Thinking Tasks (Building Thinking Classroom style).
Teacher Choice activities can be done on the whiteboard, mini-whiteboards, in small groups, or individually.
MathUP has activities such as: Brain Benders and Wonder Tasks that could be used.
Place Value Mystery Picture (coloring)
tens and ones
Technology: Fact Fluency Practice
Free; K-Gr. 6
Free; PreK to Gr. 3
Free; PreK to Gr. 5
use free account but is affordable for teachers; families are $2/child for a year
Review videos and questions for extra practice; can change the language for EAL students