60Lower Secondary big button pagehttp://nrich.maths.org/secondary-loweren 2012 http://nrich.maths.org/public/terms.phpAll about Averageshttp://nrich.maths.org/11494Wed, 01 Dec 1999 00:00:01 +0000Unequal AveragesPlay around with sets of five numbers and see what you can discover about different types of average...http://nrich.maths.org/11281Mon, 01 Sep 2014 00:00:01 +0100Garden ShedCan you minimise the amount of wood needed to build the roof of my garden shed?http://nrich.maths.org/11190Mon, 01 Sep 2014 00:00:01 +0100Perimeter ChallengeCan you deduce the perimeters of the shapes from the information given?http://nrich.maths.org/11119Mon, 01 Sep 2014 00:00:01 +0100OverlapsCan you find ways to put numbers in the overlaps so the rings have equal totals?http://nrich.maths.org/11112Mon, 01 Sep 2014 00:00:01 +0100Forwards Add BackwardsWhat happens when you add a three digit number to its reverse?http://nrich.maths.org/11111Mon, 01 Sep 2014 00:00:01 +0100Add to 200By selecting digits for an addition grid, what targets can you make?http://nrich.maths.org/11110Mon, 01 Sep 2014 00:00:01 +0100ImpossibilitiesJust because a problem is impossible doesn't mean it's difficult...http://nrich.maths.org/11109Mon, 01 Sep 2014 00:00:01 +0100CryptarithmsCan you crack these cryptarithms?http://nrich.maths.org/11107Mon, 01 Sep 2014 00:00:01 +0100Quadrilaterals in a SquareWhat's special about the area of quadrilaterals drawn in a square?http://nrich.maths.org/11105Mon, 01 Sep 2014 00:00:01 +0100Triangles in a SquareWhat are the possible areas of triangles drawn in a square?http://nrich.maths.org/11017Mon, 01 Sep 2014 00:00:01 +0100The Lives of PresidentsDo Presidents of the USA live longer now than in the past?http://nrich.maths.org/11007Mon, 01 Sep 2014 00:00:01 +0100WipeoutCan you do a little mathematical detective work to figure out which number has been wiped out?http://nrich.maths.org/10996Mon, 01 Sep 2014 00:00:01 +0100About AverageCan you find sets of numbers which satisfy each of our mean, median, mode and range conditions?http://nrich.maths.org/10995Mon, 01 Sep 2014 00:00:01 +0100Combining LengthsHow many different lengths is it possible to measure with a set of three rods?http://nrich.maths.org/10897Thu, 01 May 2014 00:00:01 +0100Climbing the StairsIn how many ways can I get upstairs?http://nrich.maths.org/10871Thu, 01 May 2014 00:00:01 +0100You Can't Make an Omelette...Can you devise the most efficient strategy for finding the highest floor from which you can drop an egg safely?http://nrich.maths.org/10870Tue, 01 Apr 2014 00:00:01 +0100Going to the CinemaA cinema has 100 seats. Is it possible to fill every seat and take exactly £100?http://nrich.maths.org/10868Thu, 01 May 2014 00:00:01 +0100Estimating TimeHow well can you estimate 10 seconds? Investigate with our timing tool.http://nrich.maths.org/10629Sun, 01 Dec 2013 00:00:01 +0000Picturing the WorldHow can we make sense of national and global statistics involving very large numbers?http://nrich.maths.org/10464Tue, 01 Oct 2013 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 +0100Always a Multiple?Think of a two digit number, reverse the digits, and add the numbers together. Something special happens...http://nrich.maths.org/7208Tue, 01 May 2012 00:00:01 +0100Dicey OperationsWho said that adding, subtracting, multiplying and dividing
couldn't be fun?http://nrich.maths.org/6606Tue, 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 +0000Reaction TimerThis problem offers you two ways to test reactions - use them to
investigate your ideas about speeds of reaction.http://nrich.maths.org/6044Tue, 01 Feb 2011 00:00:01 +0000Difference SudokuUse the differences to find the solution to this Sudoku.http://nrich.maths.org/5798Sun, 01 Dec 2013 00:00:01 +0000Method in Multiplying Madness?Watch our videos of multiplication methods that you may not have met before. Can you make sense of them?http://nrich.maths.org/5612Sat, 01 Oct 2011 00:00:01 +0100Two and TwoHow many solutions can you find to this sum? Each of the different letters stands for a different number.http://nrich.maths.org/781Tue, 01 Feb 2011 00:00:01 +0000