Exploring and noticing

There are 412 NRICH Mathematical resources connected to Exploring and noticing
Alphabet Soup
problem

Alphabet soup

Age
11 to 14
Challenge level
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This challenge is to make up YOUR OWN alphanumeric. Each letter represents a digit and where the same letter appears more than once it must represent the same digit each time.
Special 24
problem

Special 24

Age
7 to 11
Challenge level
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Find another number that is one short of a square number and when you double it and add 1, the result is also a square number.
1, 2, 3, 4, 5
problem

1, 2, 3, 4, 5

Age
7 to 11
Challenge level
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Using the numbers 1, 2, 3, 4 and 5 once and only once, and the operations x and ÷ once and only once, what is the smallest whole number you can make?
Tricky Triangles
problem

Tricky triangles

Age
5 to 7
Challenge level
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Use the three triangles to fill these outline shapes. Perhaps you can create some of your own shapes for a friend to fill?
Lawn Border
problem

Lawn border

Age
5 to 11
Challenge level
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If I use 12 green tiles to represent my lawn, how many different ways could I arrange them? How many border tiles would I need each time?
What Two ...?
problem

What two ...?

Age
7 to 11
Challenge level
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56 406 is the product of two consecutive numbers. What are these two numbers?
Sending Cards
problem

Sending cards

Age
7 to 11
Challenge level
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This challenge asks you to investigate the total number of cards that would be sent if four children send one to all three others. How many would be sent if there were five children? Six?
Lost Books
problem

Lost books

Age
7 to 11
Challenge level
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While we were sorting some papers we found 3 strange sheets which seemed to come from small books but there were page numbers at the foot of each page. Did the pages come from the same book?
Arranging the Tables
problem

Arranging the tables

Age
7 to 11
Challenge level
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There are 44 people coming to a dinner party. There are 15 square tables that seat 4 people. Find a way to seat the 44 people using all 15 tables, with no empty places.
Arrange the Digits
problem

Arrange the digits

Age
11 to 14
Challenge level
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Can you arrange the digits 1,2,3,4,5,6,7,8,9 into three 3-digit numbers such that their total is close to 1500?