And a further gem. Alex first threw a javelin 45.65m. He can now throw it three tenths further. How far can he throw now? Clearly the teacher-intended answer is 45.95m, but for units reasons I think a more correct answer is 59.345m (= 45.65m + 30%).https://twitter.com/wtgowers/status/1217193165104537600 …
The teaching of elementary mathematics has a long history. The challenges posed by the task are not new, and shrewd practitioners have pondered them at great length. Why, then, has the practice not long ago achieved optimality? Why do obvious howlers continue to infest textbooks?