It appears that the geneal standard of numeracy in the UK has been falling year on year. Whether that is due to poor teaching or a rise in a range of electronic gadgets to do sums for you, it seems that at least a third of adults over the age of 18 find it difficult to do simple sums in their head.
To see if people are having trouble they have come up with several tests reflecting the general level of maths at set ages through school. You can take a sample of the test here to see what level you are it.
Numeracy Challenge
See if you can do it without resorting to a calculator and should only take about 20 minutes.