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'Tis whole
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?
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100m sprint
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12345
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13 steps
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2-digit square
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2009 challenge
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2011 digits
What is the sum of the first $2011$ digits when $20 \div 11$ is written as a decimal?
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2D-3D
Two circles of equal size intersect and the centre of each circle is on the circumference of the other. What is the area of the intersection? Now imagine that the diagram represents two spheres of equal volume with the centre of each sphere on the surface of the other. What is the volume of intersection?
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3-sided
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30-60-90 polypuzzle
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396
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3D treasure hunt
Some treasure has been hidden in a three-dimensional grid! Can you work out a strategy to find it as efficiently as possible?
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8 methods for three by one
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A big power
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A biggy
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A brief introduction to complex numbers
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A brief introduction to the Argand diagram
Complex numbers can be represented graphically using an Argand diagram. This problem explains more...
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A circuit problem
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A close match
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A computer program to find magic squares
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A curious collection of bridges
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A different differential equation
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A drink of water
Rachel and Ross share a bottle of water. Can you work out how much water Rachel drinks?
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A frosty puddle
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A journey into stemNRICH
Follow the mathematical journey of a sixth-former as she spent four weeks working on stemNRICH problems.
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A knight's journey
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A KS5 proof collection
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A little light thinking
Here is a machine with four coloured lights. Can you make two lights switch on at once? Three lights? All four lights?
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A long time at the till
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A method of defining coefficients in the equations of chemical reactions
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A population survey
A geographical survey: answer the tiny questionnaire and then analyse all the collected responses...
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A probability conundrum
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A problem of time
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A quartet of tetrahedra
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A roll of patterned paper
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A rolling disc - periodic motion
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A sameness surely
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A scale for the solar system
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A shade crossed
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A story about absolutely nothing
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A swiss sum
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A third of the area
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A tilted square
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A very shiny nose?
This problem explores the biology behind Rudolph's glowing red nose, and introduces the real life phenomena of bacterial quorum sensing.
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Ab surd ity
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About Pythagorean golden means
What is the relationship between the arithmetic, geometric and harmonic means of two numbers, the sides of a right angled triangle and the Golden Ratio?
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Absolutely!
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Absurdity again
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AC/DC circuits
This article, including exercises, gives a thorough grounding in the topic of AC/DC circuits.
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Acceptance rate
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Addicted to addition
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Adding a square to a cube
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Adding machine
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Adding odd numbers
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Adding odd numbers (part 2)
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Adding to 400
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Additional integrals
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Adjacent additions
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Advanced mathematical problem solving resources
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Advanced mathematics on dotty grids
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Advent calendar 2020 - secondary
Our Secondary advent calendar contained twenty-four tasks for the run-up to Christmas, each one from a different past feature.
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Adventures with complex numbers
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Adventures with numbers
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Agile algebra
Observe symmetries and engage the power of substitution to solve complicated equations.
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Air nets
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Air routes
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Algorithms
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Alien currency
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All about averages
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All about ratios
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All secondary factors and multiples
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All tied up
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All-variables Sudoku
The challenge is to find the values of the variables if you are to solve this Sudoku.