Class 7 Maths Part 1 Chapter 6, Number Play, turns number theory into engaging puzzles—height-order sequences, odd/even parity arguments, $3 \times 3$ and $4 \times 4$ magic squares (including the Chautisa Yantra at Khajuraho), the Virahanka–Fibonacci sequence in poetry and nature, and cryptarithm puzzles.
What Class 7 Mathematics Chapter 6 Covers
6.1–6.2 Numbers Tell Us Things & Picking Parity solves logical ordering puzzles (‘how many taller people stand in front’) and uses odd/even parity rules for sums and products to prove when a grid tiling or coin puzzle is possible or impossible.
6.3 Some Explorations in Grids (Magic Squares) systematically constructs $3 \times 3$ magic squares using 1 to 9 (magic sum $15$, centre $5$), generalises them algebraically, and explores India’s historic $4 \times 4$ magic square at Parshvanatha temple, Khajuraho (magic sum $34$).
6.4–6.5 Virahanka–Fibonacci Numbers & Digits in Disguise discovers the sequence $1, 2, 3, 5, 8, 13, 21, \dots$ through Sanskrit prosody (short 1-beat and long 2-beat syllables studied by Pingala, Virahanka, Gopala and Hemachandra) and staircase climbs, and solves letter-digit cryptarithms.
Exercises in Chapter 6
- Figure it Out exercise sets and Summary with solved walkthroughs.
Read Class 7 Mathematics Chapter 6 Online
More Chapters
- Previous: Chapter 5: Parallel and Intersecting Lines
- Next: Chapter 7: A Tale of Three Intersecting Lines
- Hindi medium: Class 7 Maths Part 1 Chapter 6 PDF in Hindi (Ganita Prakash)
- All Mathematics chapters and the other Class 7 books: Class 7 NCERT books 2026-27
FAQ
Why must the centre number of a 3×3 magic square using the numbers 1 to 9 always be 5?
The sum of 1 to 9 is 45, so each of the three rows, columns and diagonals must add up to $45 \div 3 = 15$. Only the middle number 5 belongs to four different 3-number combinations that sum to 15, so 5 must occupy the centre cell.
How do the Virahanka–Fibonacci numbers arise from poetic metres?
Counting the number of rhythmic patterns of length $n$ beats using short syllables (1 beat) and long syllables (2 beats) gives $1, 2, 3, 5, 8, 13, 21, \dots$, where each term is the sum of the two preceding terms ($F_n = F_{n-1} + F_{n-2}$).