Maths Notes

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Factors: Numbers that multiply into a larger number equally. Eg. 6: 1,2,3,6

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A multiple: is a result of multiplying a number by an integer

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Prime numbers: are numbers that only have 1 factor, 1 and its number.

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Composite numbers: are numbers that have more than the factors of 1 and itself.

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Highest Common Factor (HCF): is the highest factor that two or more numbers have in common.

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Index numbers/index laws:

are when you have the same base multiplying. Eg. a to the power of 2 + a to the power of 3 = a to the power of 5.

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Order of operations:

Solve brackets then index then multiplication and division then finally addition and subtraction.

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Fractions

A fraction is a part of an integer. 1/3 is equivalent to the integer divided by 3 and only one part. The numerator is the top number of the fraction and the denominator is the bottom number in a fraction.

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Adding and subtracting fractions

Keep the same denominator.

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Multiplying fractions:

Multiply the numerator with the numerator and the denominator with the denominator

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Unitary method:

Find 3/8 of 496

Divide 496 by 8

Answer equals 1 part.

Multiply the answer by 3

3/8 equals 186

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Dividing fractions:

Leave, change, flip.

Leave the first fraction. Change the division sign into a multiplication sign. Flip the last fraction upside down.

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Decimals to fractions:

1) 2.1 = 2 + 2/10

2) 2.0006 = 2 + 6/1000

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Converting fractions to decimals:

Look for a denominator of 100

a) 3x4/25/4 = 12/100

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Increases and decreases of an original number:

15% of increased 550 =?

115% so 550 x 1.15 = 632.5

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Pythagoras Theorem:

a-squared + b-squared equals c-squared.

c is the largest side or angle and is always opposite the right angle.