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KS3

WATCH: Introducing algebra

Part of MathsWhat is Algebra?

Algebra uses letters to represent unknown values.
Unknown values are commonly represented by the letters x and y.
There are several principles you need to know to be able to use algebraic notation.

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Click to see a step-by-step slideshow.
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When adding a number to x we use the plus symbol and the number: x + 1.
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When multiplying x, we don't use the multiplication symbol. Put the number in front of x: 3x, 4x, 5x ...
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When multiplying x by itself (called squaring), we use the squared symbol (a small 2 in the right hand corner).
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When multiplying 2 unknowns (x and y), we don't use the multiplication symbol, just put them next to one another.

How does algebraic notation work?

Let's say that x = 5 and y = 10 in the following equations.

Therefore…

x + 2 = 7
3x = 15 (when multiplying don't include the multiplication symbol)
3x + 2 = 17
x² = 25
4x² = 100
xy = 50
2xy = 100

Where next?

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