60Upper Secondary Big Buttonhttp://nrich.maths.org/secondary-upperen 2012 http://nrich.maths.org/public/terms.phpAdvanced Mathematics on Dotty GridsA dotty grid is a very simple mathematical structure that offers potential for very deep thought...http://nrich.maths.org/10813Sat, 01 Mar 2014 00:00:01 +0000Exploring Dotty Grids at Upper Secondaryhttp://nrich.maths.org/10810Sat, 01 Mar 2014 00:00:01 +0000Getting Round the CityIn a city with a grid system of roads, how do you get from A to B?http://nrich.maths.org/10796Sat, 01 Feb 2014 00:00:01 +0000Find the MetagiffPlay the game. How many guesses do you need to find the Metagiff?http://nrich.maths.org/10749Sat, 01 Feb 2014 00:00:01 +0000Areas from VectorsUse the applet to explore the area of a parallelogram and how it relates to vectors.http://nrich.maths.org/10735Sat, 01 Feb 2014 00:00:01 +0000An Appearing ActCut out and reassemble the pieces. Can you explain what happens?http://nrich.maths.org/10711Sat, 01 Feb 2014 00:00:01 +0000Estimating TimeHow well can you estimate 10 seconds? Investigate with our timing tool.http://nrich.maths.org/10629Sun, 01 Dec 2013 00:00:01 +0000Perception Versus RealityInfographics are a powerful way of communicating statistical information. Can you come up with your own?http://nrich.maths.org/10466Tue, 01 Oct 2013 00:00:01 +0100A Brief Introduction to the Argand DiagramComplex numbers can be represented graphically using an Argand diagram. This problem explains more...http://nrich.maths.org/9859Fri, 01 Feb 2013 00:00:01 +0000A Brief Introduction to Complex NumbersIn this problem, we define complex numbers and invite you to explore what happens when you add and multiply them.http://nrich.maths.org/9858Fri, 01 Feb 2013 00:00:01 +0000Complex SquaresWhat happens when we square complex numbers? Can the square of a complex number be real?http://nrich.maths.org/8109Fri, 01 Mar 2013 00:00:01 +0000Vector JourneysCharlie likes to go for walks around a square park, while Alison likes to cut across diagonally. Can you find relationships between the vectors they walk along?http://nrich.maths.org/7453Tue, 01 Feb 2011 00:00:01 +0000Cross with the Scalar ProductExplore the meaning of the scalar and vector cross products and see how the two are related.http://nrich.maths.org/6576Tue, 01 Feb 2011 00:00:01 +0000Fix Me or Crush MeCan you make matrices which will fix one lucky vector and crush another to zero?http://nrich.maths.org/6575Tue, 01 Feb 2011 00:00:01 +0000Vector WalkStarting with two basic vector steps, which destinations can you reach on a vector walk?http://nrich.maths.org/6572Tue, 01 Feb 2011 00:00:01 +0000Power CountdownIn this twist on the well-known Countdown numbers game, use your knowledge of Powers and Roots to make a target.http://nrich.maths.org/6448Tue, 01 Feb 2011 00:00:01 +0000Power Mad!Powers of numbers behave in surprising ways. Take a look at some of these and try to explain why they are true.http://nrich.maths.org/6401Tue, 01 Feb 2011 00:00:01 +0000Data MatchingUse your skill and judgement to match the sets of random data.http://nrich.maths.org/5933Tue, 01 Feb 2011 00:00:01 +0000Odd One OutIn this short problem, can you deduce the likely location of the odd ones out in six sets of random numbers?http://nrich.maths.org/5801Tue, 01 Feb 2011 00:00:01 +0000TensWhen is $7^n + 3^n$ a multiple of 10? Can you prove the result by two different methods?http://nrich.maths.org/5562Tue, 01 Feb 2011 00:00:01 +0000GiantsWhich is the bigger, 9^10 or 10^9 ? Which is the bigger, 99^100 or 100^99 ?http://nrich.maths.org/649Tue, 01 Feb 2011 00:00:01 +0000