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Two Regular Polygons
problem

Two Regular Polygons

14 to 16

Two polygons fit together so that the exterior angle at each end of their shared side is 81 degrees. If both shapes now have to be regular could the angle still be 81 degrees?

Mach Attack
problem

Mach Attack

16 to 18

Have you got the Mach knack? Discover the mathematics behind exceeding the sound barrier.

Small tomato seedlings in pink pots.
problem

Multiplication Table Puzzle

11 to 14

In the multiplication table on the right, only some of the numbers have been given. What is the value of A+B+C+D+E?

Small pepper seedlings in turquoise pots.
problem

Two Isosceles

11 to 14

Weekly Problem 37 - 2017
A quadrilateral is divided into two isosceles triangles. Can you work out the perimeter of the quadrilateral?

Euler's Totient Function
problem

Euler's Totient Function

16 to 18
How many numbers are there less than $n$ which have no common factors with $n$?
Digital Equation
problem

Digital Equation

16 to 18
Can you find a three digit number which is equal to the sum of the hundreds digit, the square of the tens digit and the cube of the units digit?
Impossible square?
problem

Impossible Square?

16 to 18

Can you make a square from these triangles?

Cobalt decay
problem

Cobalt Decay

16 to 18

Investigate the effects of the half-lifes of the isotopes of cobalt on the mass of a mystery lump of the element.

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