Prime factor decomposition

#### Tier: #Foundation #Higher

Description

A question will nearly always be written in the following way: Express 100 as a product of its prime factors

This topic involves breaking down (decomposing) numbers into their prime factor products. For example, $100 = 2^{2}\times5^2$

Once you have all of the prime factors, you multiply them to give the final answer: $$100 = 2\times2\times5\times5$$

Because there are duplicates, we collect them together as indices: $$100 = 2^{2}\times5^2$$ A very common error is for students to write the answer as 2, 2, 5, 5. If you check the question again, it asks for the product which means multiply.

Links

Indices Set notation

Questions to practise

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ℹ️Calculator tricks

Your calculator has a FACT button which will take any number and decompose it into its prime factors Try typing 120 into your calculator then press the equals button Then press Shift and FACT. The calculator will show $2^3\times3\times5$

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