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Secondary Live Problems and Recent Solutions

Secondary Live Problems

Each time you visit the NRICH site there will be some activities which are 'live'. This means we are inviting students to send us solutions, and we will publish a selection of them, along with each student's name and their school, a few weeks later. If you'd like to know more about what we're looking for, read this short article.

The last day for sending in solutions to these live problems is Monday 27 November.

Xavi's T-shirtLive

Age 7 to 16
Challenge Level Yellow star

How much can you read into a T-shirt?

The MatrixLive

Age 14 to 18
Challenge Level Yellow star

Explore a new way of multiplying with matrices.

Flipping Twisty MatricesLive

Age 14 to 18
Challenge Level Yellow star

Investigate the transformations of the plane given by the 2 by 2 matrices with entries taking all combinations of values 0, -1 and +1.

A Powerful MatrixLive

Age 14 to 18
Challenge Level Yellow star

What happens when you find the powers of this matrix?

Markov MatricesLive

Age 14 to 18
Challenge Level Yellow star

Use matrices to find out how much cake I eat.

Square PairLive

Age 14 to 18
Challenge Level Yellow starYellow star

Explore the shape of a square after it is transformed by the action of a matrix.

Two and Four Dimensional NumbersLive

Age 16 to 18
Challenge Level Yellow star

Matrices and Complex Numbers combine to enable us to create four dimensional numbers.

Matrix MeaningLive

Age 16 to 18
Challenge Level Yellow starYellow star

Explore the meaning behind the algebra and geometry of matrices with these 10 individual problems.

Pass the ParcelLive

Age 16 to 18
Challenge Level Yellow starYellow star

Use matrices to model this popular party game.

Fix Me or Crush MeLive

Age 16 to 18
Challenge Level Yellow starYellow star

Can you make matrices which will fix one lucky vector and crush another to zero?

Transformations for 10Live

Age 16 to 18
Challenge Level Yellow starYellow starYellow star

Explore the properties of matrix transformations with these 10 questions.


 

Secondary Students' Solutions

Take a look at these recently solved problems.

Subtraction Surprise

Age 7 to 14
Challenge Level Yellow star

Try out some calculations. Are you surprised by the results?

Non-transitive Dice

Age 11 to 14
Challenge Level Yellow starYellow star

Alison and Charlie are playing a game. Charlie wants to go first so Alison lets him. Was that such a good idea?

Pair Products

Age 14 to 16
Challenge Level Yellow star

Choose four consecutive whole numbers. Multiply the first and last numbers together. Multiply the middle pair together. What do you notice?

Pick's Theorem

Age 14 to 16
Challenge Level Yellow starYellow star

Polygons drawn on square dotty paper have dots on their perimeter (p) and often internal (i) ones as well. Find a relationship between p, i and the area of the polygons.

Square Remainders

Age 16 to 18
Challenge Level Yellow star

What is the remainder if you divide a square number by $8$?

Divisible Factorisations

Age 16 to 18
Challenge Level Yellow star

Can you show that $n^5-n^3$ is always divisible by $24$?

Proper Factors

Age 16 to 18
Challenge Level Yellow starYellow star

Can you find the smallest integer which has exactly 426 proper factors?

Square Difference

Age 16 to 18
Challenge Level Yellow starYellow star

Which numbers can you write as a difference of two squares? In how many ways can you write $pq$ as a difference of two squares if $p$ and $q$ are prime?

Sissa's Reward

Age 11 to 14
Challenge Level Yellow starYellow star

Sissa cleverly asked the King for a reward that sounded quite modest but turned out to be rather large...

Square It

Age 11 to 16
Challenge Level Yellow star

Players take it in turns to choose a dot on the grid. The winner is the first to have four dots that can be joined to form a square.

Parallelogram It

Age 11 to 16
Challenge Level Yellow star

Players take it in turns to choose a dot on the grid. The winner is the first to have four dots that can be joined to form a parallelogram.

Rhombus It

Age 11 to 16
Challenge Level Yellow starYellow star

Players take it in turns to choose a dot on the grid. The winner is the first to have four dots that can be joined to form a rhombus.

Calculating with Cosines

Age 14 to 18
Challenge Level Yellow starYellow star

If I tell you two sides of a right-angled triangle, you can easily work out the third. But what if the angle between the two sides is not a right angle?

Tri-angled Trig

Age 16 to 18
Challenge Level Yellow starYellow starYellow star

Can you justify this equation involving three angles?

Trig Identity

Age 16 to 18
Challenge Level Yellow star

In this short challenge, can you use angle properties in a circle to figure out some trig identities?

T for Tan

Age 16 to 18
Challenge Level Yellow star

Can you find a way to prove the trig identities using a diagram?

Loch Ness

Age 16 to 18
Challenge Level Yellow starYellow star

Draw graphs of the sine and modulus functions and explain the humps.

Making Waves

Age 16 to 18
Challenge Level Yellow starYellow starYellow star

Which is larger cos(sin x) or sin(cos x) ? Does this depend on x ?

Degree Ceremony

Age 16 to 18
Challenge Level Yellow star

Can you find the sum of the squared sine values?

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The NRICH Project aims to enrich the mathematical experiences of all learners. To support this aim, members of the NRICH team work in a wide range of capacities, including providing professional development for teachers wishing to embed rich mathematical tasks into everyday classroom practice.

NRICH is part of the family of activities in the Millennium Mathematics Project.

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