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Number Play

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Put four cards in a row: 3, 8, 1, 6. Each card shows one digit, from 0 to 9. Swap two cards: they change places. The number changes.

Same 4 digits. A new order. A new number.

Chapter 3 of your NCERT book is Number Play.

What you will learn

  • Rearranging digits. Swap the order. Get a new number.
  • Biggest and smallest. Build the biggest and smallest number you can.
  • Palindromes. A number that reads the same both ways.
  • Supercells. A number bigger than every neighbour that touches it.
  • Estimation. A fast answer that is close to the real one.
  • Number puzzles. Clues that leave only one hidden number.
  • 6174. Biggest minus smallest, again and again.
  • Collatz. Even: halve (divide by 2). Odd: triple (multiply by 3) and add 1. Watch the numbers reach 1.
  • Number games. Work backwards to find a way to always win.

Jump to lesson

This track

  1. 0 Start here
  2. 1 Same digits, new number
  3. 2 The biggest and smallest number you can make
  4. 3 Numbers that read the same both ways
  5. 4 Spotting a supercell
  6. 5 A good estimate is fast and close
  7. 6 Hunting a number with clues
  8. 7 The magic number 6174
  9. 8 Halve it, or triple it and add 1
  10. 9 A game you can win
  11. 10 Checkpoint
  12. 11 The big picture
  13. 12 Track quiz

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