Since I grew up in the United States, learning 12 in our multiplication tables (which was also required) had a lot of value. Being able to multiply by 12 makes

Since I grew up in the United States, learning 12 in our multiplication tables (which was also required) had a lot of value. Being able to multiply by 12 makes handling inches/feet conversions a mental operation and that's something an average US citizen encounters in normal life regularly enough. I suspect in the UK this is partially due to legacy and "everyday life" usage of imperial units[1], combined with the idea that "it's really just one more number"[2]. "Officially" they are metric, but its usage varies (except temperature, which nobody can mentally calculate when I tell them it's "90 degrees out" in Fahrenheit). In the broader sense, I'd prefer that a lot more time be spent on number theory than on arithmetic. I am rarely without a smartphone to the point where its in my hands for even basic math that I could do in my head (but which, due to infrequent use, I would spend a few seconds questioning whether or not I really did get the right answer). The schools start with algebra and other concepts much earlier, now (at least my district does), but I started teaching my children formulas and basic algebra from the point they started learning to add and subtract (kindergarten in my district) along with binary and hexadecimal positional numerical systems. I remember struggling with that in my teens when I started learning software development my entire exposure to numbers was in decimal (10 is the number after 9, always!). In the first grade, my kids didn't have that mental block and I found they grasped the idea far more quickly than I expected. As they've learned multiplication and division, I've shown them the same in binary and hexadecimal and illustrated how they relate to one another. Everyone struggled being introduced algebra so late when I was growing up. And it progressed so quickly, going from Algebra (2 yrs), Geometry (1 yr), Trigonometry (1 yr) and pre-calculus/calculus that students fell mostly into either "memorize the formulas/algorithms and regurgitate the test answers or struggle like crazy and never get to Trig/Calculus until college. I left with an understanding of math but that was mostly due to my taking up programming at that time and having to learn what it all really meant because I wanted to do things in code that required me to understand it. [1] The British Metric Society "The Mess We're In" http://www.metric.org.uk/the-mess-we-are-in http://www.metric.org.uk/the-mess-we-are-in [2] The reality is that you're only asking students to memorize one more number since 10 is "add a zero and multiply by one" and 11 is an obvious pattern with single digits.