Quick - what's the square root of 2? What do you mean you don't have a calculator? Well, you can start guessing, right? So let's work this through. You know you have an upper bound - it has to be ...

Apple's Calculator app does more than help you calculate tips. With the latest OSes, it launches on iPad and lets you create a Math Note for more complex problems, among other things.

Learn about calculating the mean, mode and range from a frequency table with this BBC Bitesize Maths article. For students between the ages of 11 and 14.