CBSE Class 6 Annual Assessment

Chapter 3: Number Play

Summary

This chapter explores numbers through games, puzzles and patterns, building computational thinking. It opens with a line of children each saying the number of taller neighbours they have, showing how numbers convey information. Supercells are cells whose number is larger than all neighbouring cells; students fill grids to maximise supercells. The chapter places large numbers on number lines and counts how many 1-, 2-, 3-, 4- and 5-digit numbers exist (\(9, 90, 900, 9000, 90000\)). It studies digit sums, palindromes (numbers that read the same both ways, such as 575 or 12321), and the reverse-and-add method. A highlight is the Kaprekar constant: repeatedly making the largest minus the smallest number from a 4-digit number always reaches 6174. Clock and calendar number patterns, mental-math methods, and number-pattern sums are covered. The famous unsolved Collatz conjecture is introduced \u2014 halving even numbers and applying \(3n+1\) to odd numbers always seems to reach 1. The chapter ends with simple estimation and winning strategies for number games like reaching 21.

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Important questions

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