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Guide and features
Guide and features
Science, Technology, Engineering and Mathematics
Featured Early Years Foundation Stage; US Kindergarten
Featured UK Key Stage 1&2; US Grades 1-5
Featured UK Key Stage 3-5; US Grades 6-12
Featured UK Key Stage 1, US Grade 1 & 2
Featured UK Key Stage 2; US Grade 3-5
Featured UK Key Stages 3 & 4; US Grade 6-10
Featured UK Key Stage 4 & 5; US Grade 11 & 12
Sometimes mathematical setups which appear to be straightforward can lead to circular of self-contradictory or 'paradoxial' logic. Give your brain a workout by thinking about these scenarios
The Surprise Test
A teacher tells her class that there will be a test given on one afternoon next week. She also tells them that they will not know which day until they are told on the morning of the test.
Can this test be given on Friday
Can it be given on any other day
The universal reference book
Consider a very big book, UltraRef, which refers in its index to every book which does not refer to itself in its index.
Does UltraRef refer to itself in its index?
Smallest number paradox
Let a number N be defined to be ''The smallest whole number not definable in under eleven words''
Can N be defined in this way
My friend said ''I only ever lie''.
Was he telling the truth
The false sentence
Consider the sentence "This sentence is false"
Is the sentence true or false
The erroneous statement
Consider the statement "There are tthree errorss in this statement"
Is the statement true
Meet the team
The NRICH Project aims to enrich the mathematical experiences of all learners. To support this aim, members of the NRICH team work in a wide range of capacities, including providing professional development for teachers wishing to embed rich mathematical tasks into everyday classroom practice. More information on many of our other activities can be found here.
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Millennium Mathematics Project