World Maths Day: Can you solve Sporcle's best mathematics quizzes?

It's everybody's favourite annual celebration – World Maths Day! According to National Numeracy, an independent charity founded in 2012 to raise numeracy levels among adults and children, our maths skills are getting worse and worse, with around four in five adults affected across the UK.

Now is your chance to gets your maths up to scratch and delve into the world of puzzles. Nothing beats a good sum, so we brought you some of the most challenging ones we could find on Sporcle. They might seem easy at first, but remember – you might only have one minute to answer...