# Maths Resource of the Week 27

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#### Partly Circles

• A series of challenging GCSE circle problems.
• What is it? - This is yet another brilliant resource from the amazing Nrich. What I particularly like about this one is it is quite “old school”. No fancy interactive flash files to install, no jigsaws to cut out, just a good old fashioned challenging maths problem. What is also nice is that the problem is all about circles. Now, for this new GCSE it is crucial that higher ability Year 10 and 11 students have plenty of practice of solving difficulty, unstructured problems. Trying to find such material for circles can be a bit of a nightmare. Sticking a couple of semi-circles around a rectangle and asking for the perimeter is usually about as good as it gets. However, the three problems in this resource are incredibly challenging. They only require a basic knowledge of circle properties, pi, and area and circumference formulae, but they should stretch even the brightest of students. And as ever with Nrich, hints, follow-up work and solutions are provided.
• How could it be used? - Nrich problems lend themselves perfectly to group work. A nice lesson might involve splitting a high ability Year 10/11 class up into teams of 6, and giving each team a copy of the three problems. Encourage the students to work in pairs for five minutes on each problem before passing the problem to the next pair in the group. After 15 minutes each pair has worked on each problem, and then there could be a 10 minute discussion within groups where they try to decide upon a common correct solution. The discussions that will take place, together with the experience of co-operative learning, will serve your students very well.
• How have you used this resource? - Please share your ideas below.