List

Proof by Exhaustion

Robot Monsters
problem
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Robot Monsters

Age
5 to 7
Challenge level
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Use these head, body and leg pieces to make Robot Monsters which are different heights.
School fair necklaces
problem
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School fair necklaces

Age
5 to 11
Challenge level
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How many possible symmetrical necklaces can you find? How do you know you've found them all?
6 Beads
problem
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6 Beads

Age
5 to 7
Challenge level
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If you put three beads onto a tens/ones abacus you can make the numbers 3, 30, 12 or 21. What numbers can be made with six beads?

Sealed Solution
problem
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Sealed Solution

Age
7 to 11
Challenge level
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Ten cards are put into five envelopes so that there are two cards in each envelope. The sum of the numbers inside it is written on each envelope. What numbers could be inside the envelopes?
Reach 100
problem
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Reach 100

Age
7 to 11
Challenge level
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Choose four different digits from 1-9 and put one in each box so that the resulting four two-digit numbers add to a total of 100.

Factor Lines
problem
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Factor Lines

Age
7 to 14
Challenge level
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Arrange the four number cards on the grid, according to the rules, to make a diagonal, vertical or horizontal line.
The Dice Train
problem
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The Dice Train

Age
7 to 11
Challenge level
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This dice train has been made using specific rules. How many different trains can you make?