Question

Which number is not in scientific notation?

Select one:
a. 11 ⋅ 1021
b. 5.7 ⋅ 109
c. 3.1 ⋅ 10−12
d. 1.67 ⋅ 10−

Answer 1

All of them.

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The 4th selection is missing an exponent. (The exponent is improperly indicated in all the numbers.)