Being resilient

There are 55 NRICH Mathematical resources connected to Being resilient
Can you Make 100?
problem
Favourite

Can you make 100?

Age
11 to 14
Challenge level
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How many ways can you find to put in operation signs (+, −, ×, ÷) to make 100?
Which Scripts?
problem
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Which scripts?

Age
7 to 11
Challenge level
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There are six numbers written in five different scripts. Can you sort out which is which?
Nine-Pin Triangles
problem
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Nine-pin triangles

Age
7 to 11
Challenge level
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How many different triangles can you make on a circular pegboard that has nine pegs?

Two and Two
problem
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Two and two

Age
7 to 16
Challenge level
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How many solutions can you find to this sum? Each of the different letters stands for a different number.

Odds and Evens
problem
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Odds and evens

Age
11 to 14
Challenge level
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Are these games fair? How can you tell?
American Billions
problem
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American billions

Age
11 to 14
Challenge level
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Play the divisibility game to create numbers in which the first two digits make a number divisible by 2, the first three digits make a number divisible by 3...
Squares in rectangles
problem
Favourite

Squares in rectangles

Age
11 to 14
Challenge level
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A 2 by 3 rectangle contains 8 squares and a 3 by 4 rectangle contains 20 squares. What size rectangle(s) contain(s) exactly 100 squares? Can you find them all?
In a box
problem
Favourite

In a box

Age
14 to 16
Challenge level
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Chris and Jo put two red and four blue ribbons in a box. They each pick a ribbon from the box without looking. Jo wins if the two ribbons are the same colour. Is the game fair?
Product Sudoku
problem
Favourite

Product sudoku

Age
11 to 16
Challenge level
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The clues for this Sudoku are the product of the numbers in adjacent squares.

Same length
problem
Favourite

Same length

Age
11 to 16
Challenge level
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Construct two equilateral triangles on a straight line. There are two lengths that look the same - can you prove it?