# 1718 WB1Y CH10 Lesson 4

Which exercises/theory should I discuss on the board?
1 / 11
Slide 1: Mind map
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This lesson contains 11 slides, with interactive quizzes and text slides.

Lesson duration is: 50 min

## Items in this lesson

Which exercises/theory should I discuss on the board?

#### Slide 1 -Mind map

Using the calculator
Your calculator follows the order of operations
(calculation order):
1. Brackets
2. Powers
3. Multiply and Divide from left to right
4. Add and Subtract from left to right

#### Slide 2 -Slide

Fractions
To type a fraction you can use the division
button.

#### Slide 3 -Slide

Calculations with fractions
When doing calculations with fractions on your
calculator, remember the order of operations.
Use brackets if needed.

Calculate

26518=

#### Slide 5 -Open question

Fractions <--> Decimal numbers
You can use this button to switch your display
between fractions and decimal numbers.

#### Slide 6 -Slide

Rounding off decimal numbers
Some fractions have an infinite number of decimals.
If you type in                                   your screen will give:
2.4285714286

There should be more numbers after the decimal point, but there is not enough room on your calculator to show them all.

#### Slide 7 -Slide

Rounding off decimal numbers

The decimal number can be rounded off.
When rounding off to 1 decimal place, look at the 2nd decimal, if the 2nd decimal is a 0/1/2/3/4, leave the 1st decimal as it is. if the 2nd decimal is a 5/6/7/8/9, increase the 1st decimal by 1. (When rounding to 2 decimal places, look at the 3rd decimal, etc)
To one decimal place: 2.4               (because the 2nd decimal is a 2)
To two decimal places: 2.43          (because the 3rd decimal is an 8)
To three decimal places: 2.429     (because the 4th decimal is a 5)

#### Slide 8 -Slide

What is 2.4285714286 rounded off
to 4 decimal places?

#### Slide 9 -Open question

Approximately sign
When rounding off a decimal number you use the           -sign.
This sign means "is approximately equal to".

If a number is not rounded off, you use the        -sign.
This sign means "is (exactly) equal to".

#### Slide 10 -Slide

Homework Tuesday
Make and correct from §10.4: 19 - 28

Make and correct any exercises from Refresh, §10.2 and §10.3 you have not done yet (see studyplanner).