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Cube roots and perfect cubes

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Learn it The cube root $\sqrt[3]{x}$ asks: which number used three times as a factor makes x? It undoes cubing.

Example: Find $\sqrt[3]{343}$.

  1. Try $7 \times 7 = 49$, then $49 \times 7 = 343$.
  2. So $\sqrt[3]{343} = 7$.
  3. Tip: the ones digit helps. A cube ending in 3 comes from a number ending in 7.

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