Number Play

About this chapter

Number Play is of Class 7 Ganita Prakash Part 1. It opens with the 'taller-in-front' game where each child says how many taller children stand ahead — teaching that sequences carry information without revealing the actual values. The chapter then builds the idea of parity (even and odd numbers), proves visually that two odd numbers add to an even, settles Kishor's 5-card puzzle (five odd cards cannot sum to 30), and extends parity to subtractions, grid products, and algebraic expressions (2n, 2n-1, 3n+4). magic squares — the 1-to-9 magic square with magic sum 15 and centre 5, the generalised m-form, the 10th-century Chautisa Yantra at Khajuraho with magic sum 34, the Lo Shu square and the Navagraha and Kubera Yantras. the Virahanka-Fibonacci sequence 1, 2, 3, 5, 8, 13, 21, 34, 55... discovered by Virahanka around 700 CE in Prakrit prosody — its parity pattern O, E, O, O, E... and its appearance in daisy petals. cryptarithms (T+T+T=UT gives T=5; UT+TA=TAT). For CTET Paper 2 Maths the chapter is tested through parity rules, magic square sums, Virahanka terms, staircase-counting and cryptarithm reasoning. The four tests below — Practice 15 Q, Quiz 15 Q, Hard 15 Q, Mastery 30 Q — cover all five sections at the right depth.