What is 3 cubed?

Cubing means multiplying a number by itself three times, so 3 cubed is 3 times 3 times 3, which is 9 times 3, or 27. The name comes straight from geometry: a cube with edges of length three has a volume of 27 unit cubes, just as squaring gives the area of a square. That link is worth holding on to, because it explains why volume grows so fast when you scale something up. Double the edge of a cube and the volume goes up eightfold, which is why large animals cannot simply be scaled-up versions of small ones and why a big pot of soup takes so much longer to cool than a small one. The first few cubes are 1, 8, 27, 64 and 125, and they grow much faster than the squares. Cubing also behaves neatly with negative numbers, since the cube of a negative is negative, unlike squaring.

Cubes end in every possible digit, unlike squares, so the last digit of a cube tells you the last digit of its root.