Math warm up Fractions is perfect to develop fraction understanding & math talk. Use one math warm up each day or pair several together for a longer lesson. ALIKE & DIFFERENT 3rd & 4th JANUARY pack-- 25 slides for the month! What is a Number Sense Math Warm Up? This is a routine that can be used to develop your students number sense. It can be used as a warm up, or really at any other time during your class. Use it in morning meeting, as an exit ticket, a conversation starter, or a d