# 1819 G2X §3.Refresh

CH3 Roots
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Slide 1: Slide
WiskundeMiddelbare schoolhavoLeerjaar 2

This lesson contains 13 slides, with interactive quizzes and text slides.

Lesson duration is: 50 min

## Items in this lesson

CH3 Roots

#### Slide 1 -Slide

What does it mean when you SQUARE a number?

#### Slide 2 -Mind map

Recap: Squaring
Squaring a number means you multiply that number with itself.
The square of 5 is 25, because

For positive numbers you can think of calculating
the area of a square when you know the length
of the sides. (That is why we call it squaring)

#### Slide 3 -Slide

Recap: Squaring
You can also square fractions, decimal numbers and negative numbers, when squaring fractions  and negative numbers you use brackets:
The square of      :
The square of 0.4:
The square of -7:

#### Slide 4 -Slide

Recap: Squaring
Careful with negative signs!!!

Calculate
(9)2=
A
-18
B
18
C
-81
D
81

#### Slide 6 -Quiz

Recap: cubing
Cubing a number, also called raising a number to the third power means you multiply a number by itself and then multiply it again. The same rules for brackets and opposite numbers apply.

#### Slide 7 -Slide

Recap: divisors and prime numbers
Divisors are whole numbers that you can divide a given number by that give a whole number as a result.
The divisors of 20 are 1, 2, 4, 5, 10 and 20.
(1x20=20, 2x10=20, 4x5=20)

Prime numbers are whole numbers whose only divisors are 1 and itself. The first five prime numbers are 2, 3, 5, 7 and 11

#### Slide 8 -Slide

Recap: Rounding off
When rounding off a number, take the following steps
1) decide to how many decimal places you want to round off
2) look at the next decimal. If this is a 0, 1, 2, 3 or 4, leave the last decimal as it is. If this is a 5, 6, 7, 8, 9, add 1 to the last decimal.

5.62984
To whole numbers: 6                          To 3 decimal places: 5.630
To 1 decimal place: 5.6                      To 4 decimal places: 5.6298
To 2 decimal places: 5.63

#### Slide 9 -Slide

Recap: perimeter
The perimeter is the lengths of all edges of a

The perimeter of this triangle is 3 + 4 + 5 = 12

#### Slide 10 -Slide

Recap: writing formulas shorter
You can write formulas shorter by combining like terms.
Like terms are terms with the same variable, to the same power.

#### Slide 11 -Slide

Write down any questions you have.

#### Slide 12 -Mind map

Homework Tuesday
• Bring a calculator
• Make and correct from §3.Refresh (page 90-91):
R1, R2, R3, R4, R5, R6, R7, R8