I found the book "Secrets of Mental Math" good. Also, the Texas University Interscholastic League competitions include "Number Sense", a competition in mental math (you must write down the answer and *only* the answer in the space provided; no extraneous marks on the sheet, or additional paper, is allowed; 10 minutes, 80 questions). Here's a sample sheet: http://www.uiltexas.org/files/academics/Number-Sense-Sample-Test.pdf I competed in this throughout high school and enjoyed it thoroughly. (I also competed in Slide Rule! You should see *those* tests; I managed to find one . . .) https://www.sliderulemuseum.com/REF/TexasCompetitiveMathTestSR107.pdf -tom On Tue, Jan 15, 2019 at 8:50 PM James Propp <jamespropp@gmail.com> wrote:

I'm cutting things awfully close this month, but if any of you happen to have time to read my new essay on Wednesday morning or afternoon and send me suggestions for how to improve the essay before the evening, I'll do my best to incorporate (and, as always, acknowledge) them when I post it in the evening.

http://mathenchant.org/044-draft.pdf

Suggestions after Wednesday night are welcome too, since I can edit the essay even after I publish it. And Comments (in the Comments section of the blog) will be welcome at that time as well.

Thanks,

Jim Propp _______________________________________________ math-fun mailing list math-fun@mailman.xmission.com https://mailman.xmission.com/cgi-bin/mailman/listinfo/math-fun

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