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# When Big Gets Smaller

Keywords:
Achievement Objectives:

Achievement Objective: NA5-3: Understand operations on fractions, decimals, percentages, and integers.
AO elaboration and other teaching resources

Specific Learning Outcomes:

Solve multiplication and division problems that involve fractions.

Description of mathematics:

Number Framework Stage 8

Required Resource Materials:
Calculators.
When big gets small (Material Master 8-15).
Activity:

#### Using Number Properties

Problem: “Nara buys 0.345 kilograms of chocolates, which costs \$9.78 per kilogram. Work out the approximate cost. Is the answer less than or more than \$9.78?”

(Possible answer: 0.345 x 9.78 3 tenths of 10 = 3. So the answer is less than \$9.78.)

Use the calculator to find the cost of the chocolates and round sensibly.)

(Answer: 0.345 x 9.78 = 3.3741 = \$3.37 to the nearest cent.)

Examples: Worksheet (Material Master 8–15).

#### Understanding Number Properties:

How will you work out whether the answers to problems like 56.8 x 1.088 or 0.000123 x 567 get bigger or smaller?

#### Understanding Number Properties:

z x y is always smaller than z when y is ... (Answer: less than 1).

z x y is always bigger than z when y is ... (Answer: greater than 1).