This is a set of 12 powerpoints that gives your class speed-induced practice at mental arithmetic.
Each Daily Dozen has a set of 12 randomly selected questions using addition. One half dozen of them use numbers from 1 to 10, and the other 6 use numbers from 3 to 12 for just a little more of a challenge.
When your class starts, you can have the initial slide displayed, then, once everyone is ready, you click - each question is displayed for 5 seconds. This gives students practice at answering quickly, thereby sharpening their skills. It also helps develop concentration and perseverance in the face of challenge.
Students need only compete against themselves, but they should be able to see improvement as the days go by and may well strive to improve of their own accord.