In this video, I explain how to perform two-digit operations quickly using mental strategies. We'll cover **addition**, ...
Count back & use the relationship between addition and subtraction to subtract within 20. Warm up with a Mystery Math Mistake to find the error in DC's addition. Use ...
People often solve simple arithmetic problems, such as basic addition, subtraction, multiplication or division, in their minds. The precise mental processes they rely on to solve these problems, ...