Prove that the product of the sum of n positive numbers with the sum of their reciprocals is not less than n^2.

A circle of radius r touches two sides of a right angled triangle, sides x and y, and has its centre on the hypotenuse. Can you prove the formula linking x, y and r?

Find the polynomial p(x) with integer coefficients such that one solution of the equation p(x)=0 is $1+\sqrt 2+\sqrt 3$.

Find relationships between the polynomials a, b and c which are polynomials in n giving the sums of the first n natural numbers, squares and cubes respectively.

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

Account of an investigation which starts from the area of an annulus and leads to the formula for the difference of two squares.

An algebra task which depends on members of the group noticing the needs of others and responding.

A task which depends on members of the group noticing the needs of others and responding.

Jo has three numbers which she adds together in pairs. When she does this she has three different totals: 11, 17 and 22 What are the three numbers Jo had to start with?”

If the hypotenuse (base) length is 100cm and if an extra line splits the base into 36cm and 64cm parts, what were the side lengths for the original right-angled triangle?

Brian swims at twice the speed that a river is flowing, downstream from one moored boat to another and back again, taking 12 minutes altogether. How long would it have taken him in still water?

Take a few whole numbers away from a triangle number. If you know the mean of the remaining numbers can you find the triangle number and which numbers were removed?

What is the value of the integers a and b where sqrt(8-4sqrt3) = sqrt a - sqrt b?

Solve the system of equations: ab = 1 bc = 2 cd = 3 de = 4 ea = 6

Find all the triples of numbers a, b, c such that each one of them plus the product of the other two is always 2.

Take a complicated fraction with the product of five quartics top and bottom and reduce this to a whole number. This is a numerical example involving some clever algebra.

There is a particular value of x, and a value of y to go with it, which make all five expressions equal in value, can you find that x, y pair ?

Rotate a copy of the trapezium about the centre of the longest side of the blue triangle to make a square. Find the area of the square and then derive a formula for the area of the trapezium.

However did we manage before calculators? Is there an efficient way to do a square root if you have to do the work yourself?

Given a set of points (x,y) with distinct x values, find a polynomial that goes through all of them, then prove some results about the existence and uniqueness of these polynomials.

Robert noticed some interesting patterns when he highlighted square numbers in a spreadsheet. Can you prove that the patterns will continue?

For which values of n is the Fibonacci number fn even? Which Fibonnaci numbers are divisible by 3?

The sums of the squares of three related numbers is also a perfect square - can you explain why?

A sequence of polynomials starts 0, 1 and each poly is given by combining the two polys in the sequence just before it. Investigate and prove results about the roots of the polys.

The incircles of 3, 4, 5 and of 5, 12, 13 right angled triangles have radii 1 and 2 units respectively. What about triangles with an inradius of 3, 4 or 5 or ...?

Janine noticed, while studying some cube numbers, that if you take three consecutive whole numbers and multiply them together and then add the middle number of the three, you get the middle number. . . .

If a sum invested gains 10% each year how long before it has doubled its value?

Can you find a rule which relates triangular numbers to square numbers?

Can you find the value of this function involving algebraic fractions for x=2000?

The sum of any two of the numbers 2, 34 and 47 is a perfect square. Choose three square numbers and find sets of three integers with this property. Generalise to four integers.

Given any two polynomials in a single variable it is always possible to eliminate the variable and obtain a formula showing the relationship between the two polynomials. Try this one.

What functions can you make using the function machines RECIPROCAL and PRODUCT and the operator machines DIFF and INT?

Relate these algebraic expressions to geometrical diagrams.

Can you hit the target functions using a set of input functions and a little calculus and algebra?

What angle is needed for a ball to do a circuit of the billiard table and then pass through its original position?

Prove that 3 times the sum of 3 squares is the sum of 4 squares. Rather easier, can you prove that twice the sum of two squares always gives the sum of two squares?

To break down an algebraic fraction into partial fractions in which all the denominators are linear and all the numerators are constants you simetimes need complex numbers.

To find the integral of a polynomial, evaluate it at some special points and add multiples of these values.

Medieval stonemasons used a method to construct octagons using ruler and compasses... Is the octagon regular? Proof please.

The squares of any 8 consecutive numbers can be arranged into two sets of four numbers with the same sum. True of false?

115^2 = (110 x 120) + 25, that is 13225 895^2 = (890 x 900) + 25, that is 801025 Can you explain what is happening and generalise?

First of all, pick the number of times a week that you would like to eat chocolate. Multiply this number by 2...

Show that if you add 1 to the product of four consecutive numbers the answer is ALWAYS a perfect square.

If a two digit number has its digits reversed and the smaller of the two numbers is subtracted from the larger, prove the difference can never be prime.

By proving these particular identities, prove the existence of general cases.

If a is the radius of the axle, b the radius of each ball-bearing, and c the radius of the hub, why does the number of ball bearings n determine the ratio c/a? Find a formula for c/a in terms of n.

If x + y = -1 find the largest value of xy by coordinate geometry, by calculus and by algebra.