Cube numbers

Hello, and welcome to Myriora Maths! Square numbers make flat squares. But what if we build upwards, with blocks? Eight blocks make a cube: two by two by two. These are the cube numbers!

One block is the smallest cube: one. Two by two by two is eight. Three by three by three is twenty-seven. And four by four by four is sixty-four. They grow fast!

We write a cube number with a small three. Two cubed means two times two times two: that's eight. It's called cubed, because it makes a cube!

Why is three cubed twenty-seven? Build it in layers. Each layer is a three by three square: nine blocks. Stack three layers, and you have the cube. Three nines are twenty-seven.

Here are the cube numbers worth learning. One, eight, twenty-seven, sixty-four, and a hundred and twenty-five. And ten cubed is a thousand!

Let's try one together. What is four cubed? Remember: four times four times four. Say it out loud!

Four times four is sixteen. Sixteen times four is sixty-four. So four cubed is sixty-four!

Here's a question that catches lots of people. What is two cubed? Some people say six, because they do two times three. But cubed means three twos multiplied together: two times two times two is eight!

Your turn! What is five cubed? Pick the right card. You've got fifteen seconds, or pause the video. Go!

Time's up! Five times five is twenty-five. Twenty-five times five is a hundred and twenty-five. So five cubed is a hundred and twenty-five!

Quick review. A cube number is a number times itself, times itself again. One, eight, twenty-seven, sixty-four, a hundred and twenty-five, and ten cubed is a thousand. Build it in layers: each layer is a square. And cubed never means times three! See you next time!