Estimation and Estimation and ApproximationApproximation

Estimation and ApproximationEstimation and Approximation

YOU will Recap on rounding off a number to the

required degree of accuracy. State the rules for writing significant

figures. Round off a number to the required

number of significant figures.

Estimation and Approximation

How many oranges are there in the picture?

Estimation and Approximation

.

Estimate how many smses do YOU usually send

in a month?

Approximation

The rules for rounding off are:

If the next number is 5 or more,

round upround up.

If the next number is 4 or less,

round downround down.

Approximation

Example 1

•Round off $10.46 to the nearest 10 cents

•We will look at the nearest cent $10.46

•6 - rounding up (5 or more) $10.46 $10.50

Example 2

•Round off $4.33 to the nearest 10 cents

•We will look at the nearest cent $4.33

•3 - round downing(4 or less) $4.33 $4.30

Approximation

Turn to page 56 of your textbook and refer to example 1 and 2.

Do out the ‘Try It 1 and 2’ questions of your textbook.

Turn to page 58 of your textbook and refer to example 3 and 4.

Do out the ‘Try It 3 and 4’ questions of your textbook.

Significant figures

Refers to the number of important single digits (0 through 9 inclusive) in the coefficient of an expression in scientific notation.

3 RULES• Non-zero digits are always significant. • Any zeros between two significant digits are

significant. • All zeros at the end of a decimal, after the first

non-zero digit.

Approximation

Turn to page 62 of your textbook and refer to example 5 and 6.

Do out the ‘Try It 5 and 6’ questions of your textbook.

Turn to page 63 of your textbook and refer to example 7.

Do out the ‘Try It 7’ questions of your textbook.

This Cute Teddy Bear here will like you to do this as homework in book

Exercise 3.1 – Qns 1 to 6

Qns 10a,10b,10c

Qns 12 Exercise 3.2 – Qns 1 to 4

Qns 6

WORLD WAR II IN SINGAPORE in 1942

Estimation and Approximation During War World II, Food and medical

supplies were dangerously low, partly because shipping was in total disarray.

Protect yourself against EMERGENCIES! It is important to stock up groceries for

wartime

• STOCK UP All the discounted item for the week from NTUC!

• Round off to the nearest dollar for each item

• Estimate the total price of all the items without calculator in

2 minutes.

Item Actual Estimate

Milo $ 5.10 $ 5.00

Cup noodles $ 3.30 $ 3.00

Green Tea $ 5.60 $ 6.00

Detergent $ 11.50 $ 12.00

Multi-purpose cleaner $ 3.65 $ 4.00

Shieldtox $ 3.65 $4.00

Huggies $ 12.65 $13.00

Sunflower oil $3.95 $4.00

Campbell soup $1.85 $2.00

Lakerol $1.95 $2.00

Total $53.20 $55.00

•A group of Civil Engineers were at a conference being held in Central Australia. As part of the conference entertainment, they were taken on a tour of the famous rock, Uluru.

• "This rock", announced the guide, "is 50 000 004 years old."

•The engineers - always impressed by precision in measurement - were astounded. "How do you know the age of the rock so precisely?" asked one of the group.

•"Easy!", came the reply. "When I first came here, they told me it was 50 million years old. I've been working here for 4 years now."

A StORY……