This is a tester for cube roots. It picks a random number from 10 to 100, and tells you its cube, asking you to find the cube root. If you fail you can try again. You are timed, and have a high score and average. Post your best scores in the comments below!
You will ask how to find the cube root of a 2-digit number. It's very simple actually. First, memorise this table of cubes up to 10 1 2 3 4 5 6 7 8 9 10 1 8 27 64 125 216 343 512 729 1,000 Let say it cubes 67. It will say 300,763. In order to work it out, you need to do 2 things. Firstly, look at the numbers before the comma,here 300. Which is the biggest cube smaller than 300? It is 216, 6 cubed. The answer is therefore in the 60s;it begins with a 6. To find the second digit, simply look at the last digit of the cube, here 3. Which cube ends in 3. It's 343, which is 7 cubed. Therefore the last digit is 7. And indeed, we find the number is 67. I got this from Arthur Benjamin's brilliant book Think like a Maths Genius, which has loads of great techniques for everything from multiplying 4 digit numbers in their head to creating magic squares.
