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CHAPTER AT A GLANCE
Number Play
•Unit: Number System
•Board weightage: Number patterns, digit sums, palindromes, Kaprekar's process, Collatz sequence, reasoning about 4-digit and 5-digit numbers and estimation give regular 1-mark, 2-mark, 3-mark and 4-mark questions in school examinations (please check your school's latest sample paper)
•Key ideas from the textbook: reasoning about arrangements, supercells, digit sums, counting numbers by the number of digits, palindromes, reverse and add, Kaprekar constant 6174, clock and date palindromes, estimation, Collatz conjecture
•Most scoring part: writing every step of a process (for example the A, B and C steps in Kaprekar's process) and giving a reason for always, sometimes or never statements
•Time to revise: about 55 minutes
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