AC9M5N08Year 5NumberPractised on site

AC9M5N08 — Year 5 Number

Official Curriculum Content Description:

check and explain the reasonableness of solutions to problems including financial contexts using estimation strategies appropriate to the context

Worked Examples (1)

Example 1Financial Calculations & Reasonableness
Liam buys 55 novels at $9.95\$9.95 each and pays with a $60\$60 note. A student claimed the total cost is $79.60\$79.60. Is this calculation reasonable?
Common mistake: Selecting an unreasonable estimate that misjudges magnitude or rounding direction
Correct Answer:No, estimated total is about $50\$50, which is much less than $79.60\$79.60
Worked Solution:
Check reasonableness using estimation: - Estimated price per item: $10\$10 - Estimated total: 5×$10=$505 \times \$10 = \$50 Since $79.60\$79.60 is far above $50\$50, the student's answer is not reasonable.

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