Arithmetic

It is important not to overlook the arithmetic section of the course. The questions here can be subtly tricky.
These are the main pitfalls we went through in class:
Ratios:
If there are fractions, multiply the entire ratio by the Lowest Common Denominator before you start to work out the individual shares. So 1/2 : 1/4 : 1 becomes 2:1:4 when you multiply across by 4.
Distance Speed and Time:
Be careful subtracting 24hour clock questions - we talked about the different ways of doing this - stick with whatever works best for you, but double check your answer. Make sure that you don't treat 3h20mins as 3.2 hours. Work in fractions.
Finding average speed over a 2-part journey, don't add the 2 speeds and divide by 2, DO divide the total journey time by the total time taken.
Percentages + Tax
If you are going to use the % button on your calculator, make sure you know how to use it properly. If you want to find 19% of a number you can divide by 100 and multiply by 19 or just multiply by 0.19. To add 19% on in one step, just multiply by 1.19. You don't really need the percentage button at all.
For questions such as "a bill including VAT at 12% comes to €106.40, what was the bill before tax was added" you need to write down
106.4 = 112%
then divide accross by 112 to find 1% then multiply by 100 to find 100%.
The compound interest formula is useful for working out the original principle after n years of the same rate of interest being applied. One of the homework questions requires you to use it. Set up an equation using the formula and solve it.

We will try to finish off Arithemtic in the next class.