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The calculator is not given to the student until question 4. Questions leading up to Q4 are solved mentally. In this activity we are using some artificial money. Apples at a shop cost $1.95 a kilogram. Show the advertisement card and hand out money. |
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|
%
responses
2001 ('97) |
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y4
|
y8
|
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| I
want to buy 5 kilograms of apples.I have a $5 note, a $10 note and a $20
note. 1. What is the smallest value note that I could use to pay for the apples? |
$10
|
47
(39)
|
86
(92)
|
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| 2. Why did you choose that note? |
calculation
|
2 (1)
|
11
(3)
|
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|
estimation
and elimination
|
27
(14)
|
46
(49)
|
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|
estimation,
but not eliminating $20 option
|
18
(17)
|
28
(31)
|
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| 3. How much change would you expect? |
25¢
|
7
(8)
|
33
(35)
|
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| Hand
student a calculator. Use the calculator to work out the next problem. Tell me what you are doing with the calculator as you do it. |
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| Year
8 4. If I bought a 5 kilogram bag of apples on special for $7.50, how much would the apples cost per kilogram? Ask the student to read out the answer shown on the calculator. |
$1.50
|
•
|
57 (70) | ||||||||||
| Year
4 4. If apples cost $1.50 a kilogram, how much would five kilograms cost? Ask the student to read out the answer shown on the calculator. |
$7.50
|
26
(24)
|
•
|
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| Commentary Although most year 8 students realised that a $10 note would be sufficient in question 1, few realised that the total amount required would be 5x5 cents less than $10, making the answer to question 3 easy. |
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