CBSE · Class 7 · Mathematics · Chapter 6

Number Play

Discover patterns, properties, puzzles and strategies that reveal interesting relationships between numbers.

10 lessons 50 min
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Lessons in this chapter

  1. 1Numbers Tell us ThingsDiscover how a short sequence can describe the order of people in a line.
  2. 2Picking ParityUse pairs to explain which sums and differences are possible.
  3. 3Parity in Grids and ExpressionsSee how parity can be predicted for products and algebraic expressions.
  4. 4Some Explorations in GridsUse row and column totals to solve number grids and spot impossible clues.
  5. 5Constructing a Magic SquareReason your way to a 3 × 3 square in which every line has the same sum.
  6. 6Generalising Magic SquaresTransform and describe magic squares using a letter for the centre.
  7. 7Rhythms and the Virahāṅka–Fibonacci NumbersCount rhythms of short and long syllables without missing an arrangement.
  8. 8Exploring the Virahāṅka SequenceExtend the rhythm-count sequence and discover its parity pattern and staircase connection.
  9. 9Digits in DisguiseSolve letter-and-digit puzzles with place value and carrying.
  10. 10Chapter Summary and PracticeBring the chapter’s number puzzles together and choose a reasoned method for each.
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