Explaining, convincing and proving
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problemIf you take four consecutive numbers and add them together, the answer will always be even. What else do you notice? -
problemRussian Cubes
I want some cubes painted with three blue faces and three red faces. How many different cubes can be painted like that? -
problemNatural Sum
The picture illustrates the sum 1 + 2 + 3 + 4 = (4 × 5)/2. Prove the general formula for the sum of the first n natural numbers and the formula for the sum of the cubes of the first n natural numbers.
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problemThe London Eye
The 80 spokes of The London Eye are made from 4 miles of cable. What is the approximate circumference of the wheel?
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problemDifferent Products
Take four consecutive whole numbers. Multiply the first and last numbers together. Multiply the middle pair together. What do you notice?
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problemProximity
We are given a regular icosahedron having three red vertices. Show that it has a vertex that has at least two red neighbours.
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problemGift of Gems
Four jewellers share their stock. Can you work out the relative values of their gems? -
problemLong Short
What can you say about the lengths of the sides of a quadrilateral whose vertices are on a unit circle? -
problemJanine's Conjecture
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. Does this always work? Can you prove or disprove this conjecture?