# Maths Revision

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Maths General:

Fractions:

- When adding fractions there needs to be a common denominator e.g. 1/3 and 2/3

- If you have two fractions that have different denominators then you must maker them the same e.g. 1/3 and 3/4

- In order to do this multiply the denominators together e.g. 3 x 4. This gives you 12, which is now the common denominator.

- Then you must also multiply the numerator by the number that you multiplied the denominator of that fraction by e.g. 1 x 4, and 3 x 3. This gives you  the numerator for your two new fractions with a common denominator.

- Now add the two new fractions together e.g. 4/12 + 9/12 = 13/12

- Then simplify your final answer. In this case the example cannot be simplified.

Multiplying fractions:

- When mulitplying fractions, you do not need a common denominator.

- Multiply the two top numbers together and then the two bottom number together. This gives you the answer e.g. 1/3 x 3/4 = 3/12

Subtracting fractions:

- For subtracting you need a common denominator like in adding fractions.

- The instead of adding them, subtract them e.g. 9/12 - 4/12 = 5/12

Dividing fractions:

- When dividing fraction you do not need a common denominator

- Turn one of your two fractions upside down and change the divide sign into a multiply sign e.g. 1/3 / 3/4 = 1/3 x 4/3

- Now answer this like a normal multiplication of fractions e.g. 1/3 x 4/3 = 4/9

Simplifying fractions:

- Simplifying fractions means getting a fraction to its simplest form e.g 3/6 = 1/2 however 1/2 is the simplest for of this fraction.

- In order to simplify a fraction just find a common factor of the numerator and denominator and divide them both by it. Keep dividing using different numbers at different points, until the fraction is as simple as possible.

Scale Factors:

- Linear factor = length ratio

- Area Factor = Scale Factor squared

- Volume Factor = Scale Factor