The slideshow below gives a series of number talks that can be used at the start of lessons, for a sequence of 10 lessons. They increase in difficulty and give students an overview of strategies for performing different operations.
A resource to support the use of number talks in your classroom will be this book: Building Powerful Numeracy for Middle and High School Students by Pamela Weber Harris.
Warm-Ups
There are many ways to begin a lesson. This resource includes a progression of warm-up activities, problems and questions that can be used to activate prior learning, work with patterns, make estimates, etc.