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CHAPTER AT A GLANCE
Number Play
•Unit: Number System
•Board weightage: Number Play gives 1-mark, 2-mark and 3-mark questions on parity, divisibility rules, remainders, digital roots and cryptarithms (please check the latest sample paper)
•Key ideas from the textbook: parity of sums, multiples and factors (always, sometimes, never true), divisibility by 3, 9 and 11, digital root, cryptarithms
•Most scoring part: divisibility tests with unknown digits and reasoning with algebraic forms such as 5k + 3
•Time to revise: about 60 minutes
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