My personal favourite use of Scratch is to demonstrate relationships between angles and polygons which I have written on before.
Investigating more projects on Scratch I found What’s My Number? which could make an interesting starter problem. Why can one always guess in 7 tries or less?
(See Guess My Number (Birmingham Grid for Learning) – an alternative version of the game.)
For those who wish to learn more about Scratch syntax then looking at the code for a project such as this quadratic equation solver by proanimator is helpful. Select See Inside to see the code. If you create an account (free) you can save a copy to your own account. This code could easily be adapted as it offers the means to input some variables, perform calculations and display the results. Looking at code already written can be a great way to learn syntax – it’s certainly something I have done when learning to write Excel macros.