Number 5
2 marks · NormalExplain why writing 0.037 as is correct, and why is not considered standard form.
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Standard form requires a number between 1 and 10 times a power of 10; 3.7 × 10^{-2} fits, but 37 × 10^{-3} does not, as 37 is not in [1, 10).
Also accept: 'Because 3.7 is between 1 and 10, so it fits the form' etc.
Common mistakes: Saying 37 × 10^{-3} is equivalent (it is, but not standard form)
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Marking points
B1 · 1 mark · States or implies standard form requires a × 10^n with 1 ≤ a < 10.
A1 · 1 mark · Explains why 3.7 × 10^{-2} is standard form and 37 × 10^{-3} is not.
Worked solution
0.037 = 3.7 × 10^{-2}. Standard form is a × 10^n with 1 ≤ a < 10 and n an integer. 37 × 10^{-3} is not valid standard form because 37 is not between 1 and 10.