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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……