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%
responses
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y4
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y8
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Questions/instructions Show student photo This picture shows a busy motorway. During the day time, about 98 cars go down this road every minute. |
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| 1. About how many cars would go down the road in 9 minutes? |
882
|
2
|
18
|
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|
900
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4
|
17
|
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|
any
other answer between 850 and 899
|
5
|
13
|
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| 2. Explain to me how you got your answer. |
multiply
98 9
|
31
|
48
|
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|
multiply
100 9, then subtract 9 2
|
1
|
9
|
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|
multiply
100 9, then say answer is a little less than that
|
2
|
3
|
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|
multiply
100 9, then say answer is near that
|
4
|
16
|
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| Commentary Only 48 percent of year 8 students and 11 percent of year 4 students made an accurate calculation or good approximation. In part, this was because many students tried to use the standard multiplication approach with the original numbers, rather than adjusting the 98 to 100. Only 28 percent of year 8 students and 7 percent of year 4 students used that simplification. |
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