# Refresh

Before we start the chapter we need to remember some of the things we have learnt before.
• When doing calculations we must remember the order of calculation BIDMAS
• when we raise a negative number to a power we need to see id power is odd or even
• Multiply fractions
• Multiply square roots
• write formulas shorter
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Slide 1: Tekstslide
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In deze les zitten 14 slides, met tekstslides.

## Onderdelen in deze les

Before we start the chapter we need to remember some of the things we have learnt before.
• When doing calculations we must remember the order of calculation BIDMAS
• when we raise a negative number to a power we need to see id power is odd or even
• Multiply fractions
• Multiply square roots
• write formulas shorter

#### Slide 1 -Tekstslide

Order of calculation
e.g.  32- 4 x (16-5x2) =
first do what's in brackets
32 - 4 x(16-10) =
32 - 4 x 6 =
then do multiplication
32 - 24 =
and finally the subtraction  32 -24 = 8

Even powers
and

52=55=25
(5)2=(5)(5)=25

#### Slide 3 -Tekstslide

Odd Powers
but
53=555=125
(5)3=(5)(5)(5)=125

#### Slide 4 -Tekstslide

To add fractions both fractions need to have the same denominator.
(that is the number on the bottom row of the fraction!)

#### Slide 6 -Tekstslide

Multiplying fractions
Multiply numerators together and divide by
denominators multiplied together

#### Slide 8 -Tekstslide

the numbers under the square root sign must be the same
then you can add them together

#### Slide 10 -Tekstslide

multiplying square roots
square roots can be multiplied by multiplying the numbers under the root signs.

#### Slide 12 -Tekstslide

Finally
when you need to shorten formulas you will need to remember
• you can only add terms  if they are like
• you need to remove brackets by multiplying
• be careful with powers

#### Slide 13 -Tekstslide

Homework
Do all refresh exercises R1 t/m R7