60Lower Secondary big button pagehttp://nrich.maths.org/secondary-loweren 2012 http://nrich.maths.org/public/terms.phpFactorise This!http://nrich.maths.org/13056Wed, 01 Dec 1999 00:00:01 +0000Red Card Blue CardCan you arrange the red and blue cards so that the rules are all followed?http://nrich.maths.org/12808Wed, 01 Dec 1999 00:00:01 +0000Angles in Three SquaresDrawing the right diagram can help you to prove a result about the angles in a line of squares.http://nrich.maths.org/11852Wed, 01 Dec 1999 00:00:01 +0000Common Remainder144 divided by n leaves a remainder of 11. 220 divided by n also leaves a remainder of 11. What is n?http://nrich.maths.org/11715Fri, 01 Sep 2017 00:00:01 +0100Equal MeansWhat value of x makes the mean of the first three numbers in this list equal to the mean of the other four?http://nrich.maths.org/11697Fri, 01 Sep 2017 00:00:01 +0100An Equilateral Triangular ProblemTake an equilateral triangle and cut it into smaller pieces. What can you do with them?http://nrich.maths.org/11501Wed, 01 Dec 1999 00:00:01 +0000Polygon PicturesCan you work out how these polygon pictures were drawn, and use that to figure out their angles?http://nrich.maths.org/11498Wed, 01 Dec 1999 00:00:01 +0000Star PolygonsDraw some stars and measure the angles at their points. Can you find and prove a result about their sum?http://nrich.maths.org/11456Wed, 01 Dec 1999 00:00:01 +0000Hollow SquaresWhich armies can be arranged in hollow square fighting formations?http://nrich.maths.org/11257Mon, 01 Sep 2014 00:00:01 +0100Difference of Two SquaresWhat is special about the difference between squares of numbers adjacent to multiples of three?http://nrich.maths.org/11120Mon, 01 Sep 2014 00:00:01 +0100Pythagoras PerimetersIf you know the perimeter of a right angled triangle, what can you say about the area?http://nrich.maths.org/11106Mon, 01 Sep 2014 00:00:01 +0100Quadratic PatternsSurprising numerical patterns can be explained using algebra and diagrams...http://nrich.maths.org/11011Mon, 01 Sep 2014 00:00:01 +0100Magic 7Can you complete this magic square with the numbers from 7 to 15?http://nrich.maths.org/10184Tue, 01 Sep 2015 00:00:01 +0100Olympic MeasuresThese Olympic quantities have been jumbled up! Can you put them back together again?http://nrich.maths.org/8318Fri, 01 Jun 2012 00:00:01 +0100Charting SuccessCan you make sense of the charts and diagrams that are created and used by sports competitors, trainers and statisticians?http://nrich.maths.org/7735Mon, 01 Aug 2011 00:00:01 +0100Olympic Records
Can you deduce which Olympic athletics events are represented by the graphs?
http://nrich.maths.org/7489Wed, 01 Jun 2011 00:00:01 +0100Who's the Best?Which countries have the most naturally athletic populations?http://nrich.maths.org/7367Wed, 01 Jun 2011 00:00:01 +0100Speed-time Problems at the OlympicsHave you ever wondered what it would be like to race against Usain Bolt?http://nrich.maths.org/7322Wed, 01 Jun 2011 00:00:01 +0100Trapezium ArchWeekly Problem 27 - 2007<br />
Ten stones form an arch. What is the size of the smallest angles of the trapezoidal stones?http://nrich.maths.org/5670Sun, 01 Jul 2007 00:00:01 +0100Medal MuddleCountries from across the world competed in a sports tournament. Can you devise an efficient strategy to work out the order in which they finished?http://nrich.maths.org/661Tue, 01 Feb 2011 00:00:01 +0000Counting FactorsIs there an efficient way to work out how many factors a large number has?http://nrich.maths.org/480Tue, 01 Feb 2011 00:00:01 +0000Latin NumbersCan you create a Latin Square from multiples of a six digit number?http://nrich.maths.org/434Tue, 01 Feb 2011 00:00:01 +0000Rationals Between...What fractions can you find between the square roots of 65 and 67?http://nrich.maths.org/344Tue, 01 Feb 2011 00:00:01 +0000Gift of GemsFour jewellers share their stock. Can you work out the relative values of their gems?http://nrich.maths.org/330Tue, 01 Feb 2011 00:00:01 +0000Building TetrahedraCan you make a tetrahedron whose faces all have the same perimeter?http://nrich.maths.org/272Tue, 01 Feb 2011 00:00:01 +0000Calendar CapersChoose any three by three square of dates on a calendar page...http://nrich.maths.org/85Tue, 01 Feb 2011 00:00:01 +0000