Why do we have order of operations rules in arithmetic instead of just strictly evaluating expressions from left to right (possibly with parenthesis for grouping if we really wanted to change the order)?
What are some of the newest methods being used these days to teach young children arithmetic? [more inside]
I'm taking a standardized test on Wednesday with the Government of Canada and they ask individuals four types of questions. The type that I struggle with are the arithmetic problems... specifically determining the formulas to solve word problems. I was hoping someone might be able to point me in the direction of a website or easily accessible textbook to practice today and tomorrow before the test. [more inside]
We want to assess a list of vendors in two domains: Accessibility and Cost. We have two tools that we are using to essentially score them in each of these domains separately. The Accessibility assessment tool totals 110 points; the Cost tool totals 90 points. We want a final score for each vendor that combines the domains and is out of 100. We want the Accessibility score to "count" about 20% more than the Cost score in the final because it is more important to us. How do we do this? [more inside]
Harmonic or Arithmetic Mean?: I'm trying to settle an argument with my wife - is using the arithmetic mean or harmonic mean more appropriate when finding the "average" number of, say, online comments made by a large number of people, where a significant portion of them make only one comment and a few people make the bulk of the comments? [more inside]
Basically, what it says. I've been brushing up on my math skills via Khan Academy, and I'm running into a problem I hit when I was in school. Basically, the math *concepts*, like Algebra, Trig, and the like? I'm able to get really easily. But, manipulating the numbers and doing the basic arithmetic? Hard. Sometimes even with a calculator, I'll miss carrying over a negative sign, and I'll get the problem wrong, despite knowing the concepts really, really well. What's going on here? Is my ADHD not under control? Are these symptoms of Dyscalculia? What? Ideas, hivemind! [more inside]
What is the difference between floating point accuracy and precision?
I've seen people compute complex arithmetic off the top of their head. How do they do it? [more inside]
ABC x D = BADC. What single numbers (1-9) do the letters represent? Is there any way to arrive at the answer (a) by logical deduction all the way rather than with some trial-and-error and (b) so that a 10-year-old can follow the logic? [more inside]