In our classroom we like to warm up before math instruction by having the students work in a Monthly Math Journal.  The Monthly Math Journal Pack covers all the kindergarten math standards and is a great way to review concepts previously taught in class. You can
either read the prompt and have students problem solve the answer independently, or complete the prompts guided. Some of the prompts are very basic and are good for the beginning of the school year while some are more difficult and meant for the end of the year