It’s been a while since I’ve complained about PEMDAS, so now’s a good time. We make a big deal about pointing out that multiplication is commutative, and that addition is commutative, meaning that it doesn’t matter what order we perform either one in. For instance, 4 + 3 + 5 = (4 + 3) +…
Tag: mathematics education
Operations on Fractions
A tale of carts and horses. My child is in fifth grade. Last Friday, we received the second volume of his mathematics workbook. It starts with multiplication of fractions; the next chapter is division of fractions. Addition (and subtraction) of fractions with different denominators is in the first volume. I believe this order persists partly…