In this video, I explain how to perform two-digit operations quickly using mental strategies. We'll cover **addition**, ...

What are you like at multiplications? Chances are if you're a mere mortal 2, 5s and 10s won't seem too taxing. But when it comes to figuring out what 42x21 is, you may wish somebody had shown you the ...

Add Yahoo as a preferred source to see more of our stories on Google. This math trick can help you multiply any two-digit number by 11. Arlene Resendiz is TikTok’s resident math whiz. When she’s not ...

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Numberphile revived an ancient multiplication trick—halves and doubles—also called Egyptian or Russian math, where you repeatedly halve one number and double the other. After crossing out rows with ...