Cube numbers
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You should understand what it means to cube a number, and understand that cube rooting is the inverse (opposite) operation. You should recognise cube numbers up to 5 x 5 x 5. You should also know that 10 cubed is 1000.
When you cube a number, you multiply it by itself three times. You will often see a little 3 written at the top-right hand corner of the number to show that you are cubing it. It is very important to remember that this little 3 means "cube" and not "multiply by 3"! When a number is written at the top-right hand corner of a number, it shows that you are raising the big number to the power of the little number. So we could say "to the power of 3" rather than "cubed". These little numbers are also known as indices. |
Click to watch a video demonstration of cube numbers (via YouTube)
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Cube-rooting is the inverse operation of cubing. They go together in a pair like addition and subtraction, or multiplication and division, because they are opposites of each other. When you see a cube root sign (like the little tick mark used for a square root, but with a little 3 outside it), you need to try to work out what number multiplied by itself three times gives the number under the square root sign. For example, the cube root of 8 is 2, because 2 x 2 x 2 = 8.
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