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A short way to write a long multiplication

Start with one cell. Every cell splits in two each hour. After five hours there are 32 cells.

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2⁵ — the short way to write it.
Step 1 of 4
  1. 2⁵ — the short way to write it.
  2. Opened out: 2 × 2 × 2 × 2 × 2.
  3. Five 2s. Base 2, exponent 5.
  4. Multiplied out: 32.

The rule

A power is a short way to write repeated multiplication. It has a base and an exponent. The base is the number you multiply. The exponent counts how many. The exponent is also called the count. 2⁵ is five 2s multiplied: 32. Each copy of the base is a factor.

  • 5² is read five squared. 5³ is five cubed.
  • Above 3, say "to the power" and the exponent. 2⁴ is two to the power four.
  • 5³ = 5 × 5 × 5 = 25 × 5 = 125.
  • A power multiplies. 3 + 3 + 3 + 3 is 12, but 3 × 3 × 3 × 3 is 81.

Jump to lesson

This track

  1. 0 Start here
  2. 1 A short way to write a long multiplication
  3. 2 Two powers of one number, multiplied
  4. 3 Two powers of one number, divided
  5. 4 One power stacked on another
  6. 5 Walking the ladder down to zero
  7. 6 Every column is a power of ten
  8. 7 Writing a number too long to say
  9. 8 Which of two powers is larger
  10. 9 Counts below zero
  11. 10 Writing a very small number
  12. 11 Checkpoint: small powers and small numbers
  13. 12 The big picture
  14. 13 Track quiz

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