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Hard Math for Elementary School is new category of math book. The author, MIT professor Glenn Ellison, calls it a math enrichment textbook. The idea is to make it easy for teachers or parents to supplement what kids are getting in school with with complementary lessons that are harder, deeper, and more fun.
Hard Math has chapters to accompany most textbook topics: addition with carrying, multiplication, fractions, etc. It covers other important topics – prime numbers, counting, probability -…”