NCERT Solutions for Ganita Prakash Chapter 3 Number Play
Updated on 2026-09-05
About this chapter
Numbers do more than count. They can carry information — in this chapter each child in a line says the number of taller neighbours they have. A cell is a supercell if the number written in it is greater than the numbers in all its neighbouring cells. In a single row of n cells you can get at most ⌈n ÷ 2⌉ supercells by filling the big numbers in alternate cells. The digit sum of a number is found by adding its digits (6 + 8 = 14 for 68). A palindrome reads the same from both ends — 66, 848, 12421. Kaprekar's routine — largest number minus smallest number made from the same four digits, again and again — always lands on 6174 . With 3-digit numbers it always lands on 495 . The Collatz rule (even → take half; odd → 3 × it + 1) seems to bring every number down to 1, but nobody in the world has
- Numbers can Tell us Things
- Supercells
- Patterns of Numbers on the Number Line
- Playing with Digits
- Digit sums of numbers
- Digit Detectives & Section 3.5 Pretty Palindromic Patterns
- The Magic Number of Kaprekar
- Clock and Calendar Numbers
- Mental Math
- Digits and Operations
Exercises
- In-text Questions — Numbers can Tell us Things Page 55 & 56
- In-text Questions — Numbers can Tell us Things Page 56
- Figure it Out — Supercells Page 57 & 58
- In-text Questions — Supercells Page 58 & 59
- In-text Questions — Patterns of Numbers on the Number Line Page 59
- Figure it Out — Patterns of Numbers on the Number Line Page 59
- In-text Questions — Playing with Digits Page 60
- Figure it Out — Digit sums of numbers Page 60
- Digit Detectives & Section 3.5 Pretty Palindromic Patterns — In-text Questions Page 61 & 62
- In-text Questions — The Magic Number of Kaprekar Page 63
- In-text Questions — Clock and Calendar Numbers Page 64
- Figure it Out — Clock and Calendar Numbers Page 64 & 65
- In-text Questions — Mental Math Page 65 & 66
- Figure it Out — Digits and Operations Page 66 & 67
- In-text Questions — Playing with Number Patterns Page 67 & 68
- In-text Questions — An Unsolved Mystery Page 68 & 69
- Figure it Out — Simple Estimation Page 69 & 70
- In-text Questions — Estimate the answer Page 70 & 71
- In-text Questions — Games and Winning Strategies Page 71 & 72
- Figure it Out — Games and Winning Strategies Page 72 & 73