Expanding and factorising quadratics

There are 38 NRICH Mathematical resources connected to Expanding and factorising quadratics
Powerful Factors
problem

Powerful Factors

Age
16 to 18
Challenge level
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Use the fact that: x²-y² = (x-y)(x+y) and x³+y³ = (x+y) (x²-xy+y²) to find the highest power of 2 and the highest power of 3 which divide 5^{36}-1.
Number rules - OK
problem

Number rules - OK

Age
14 to 16
Challenge level
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Can you produce convincing arguments that a selection of statements about numbers are true?
Iff
problem

Iff

Age
14 to 18
Challenge level
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Take a triangular number, multiply it by 8 and add 1. What is special about your answer? Can you prove it?
Parabella
problem

Parabella

Age
16 to 18
Challenge level
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This is a beautiful result involving a parabola and parallels.
Why 24?
problem

Why 24?

Age
14 to 16
Challenge level
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Take any prime number greater than 3 , square it and subtract one. Working on the building blocks will help you to explain what is special about your results.
What's Possible?
problem

What's Possible?

Age
14 to 16
Challenge level
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Many numbers can be expressed as the difference of two perfect squares. What do you notice about the numbers you CANNOT make?
Fair Shares?
problem

Fair Shares?

Age
14 to 16
Challenge level
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A mother wants to share a sum of money by giving each of her children in turn a lump sum plus a fraction of the remainder. How can she do this in order to share the money out equally?
Never Prime
problem

Never Prime

Age
14 to 16
Challenge level
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If a two digit number has its digits reversed and the smaller of the two numbers is subtracted from the larger, prove the difference can never be prime.
Plus Minus
problem

Plus Minus

Age
14 to 16
Challenge level
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Can you explain the surprising results Jo found when she calculated the difference between square numbers?
How old am I?
problem

How old am I?

Age
14 to 16
Challenge level
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In 15 years' time my age will be the square of my age 15 years ago. Can you work out my age, and when I had other special birthdays?