Kids who are taught less formal maths end up doing better at questions that have extra information to throw you off.

The distance from Boston to Portland by water is 120 miles. Three steamers leave Boston, simultaneously, for Portland. One makes the trip in 10 hours, one in 12, and one in 15. How long will it be before all 3 reach Portland?

So 15 hours. People who learn more plain arithmetic maths assume that the 120 miles and the fact that all the figures divide into it exactly must be significant, and try to do calculations when none are needed.

Thanks for your reply. I thought there was a point being made about education at a more meta level, since the piece was very old and it begs the question of why a really old essay is on hackernews.