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problem
Sum up
14 to 16
David listed ten consecutive numbers and removed one of them. Which number did he remove?
problem
Semicircle in a triangle
14 to 16
A semicircle is drawn inside a right-angled triangle. Find the distance marked on the diagram.
problem
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Fitted
7 to 11
Nine squares with side lengths 1, 4, 7, 8, 9, 10, 14, 15, and 18 cm can be fitted together to form a rectangle. What are the dimensions of the rectangle?
problem
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Twisting and turning
11 to 14
Take a look at the video and try to find a sequence of moves that will untangle the ropes.
problem
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Times tables shifts
7 to 11
In this activity, the computer chooses a times table and shifts it. Can you work out the table and the shift each time?
article
Sprouts explained
This article invites you to get familiar with a strategic game called "sprouts". The game is simple enough for younger children to understand, and has also provided experienced mathematicians with significant food for thought.
problem
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Two ladders
14 to 16
Two ladders are propped up against facing walls. At what height do the ladders cross?