Question

Which number is not in scientific notation?

Group of answer choices

1.45 ⋅ 10−7

0.33 ⋅ 10−15

9 ⋅ 1019

7.8 ⋅ 106

Answer 1

In scientific notation, a number is expressed in the form \( a \times 10^n \), where \( a \) is a coefficient that is at least 1 but less than 10, and \( n \) is an integer.

Let's analyze each option:

1. \( 1.45 \cdot 10^{-7} \) - This is in scientific notation (coefficient is between 1 and 10).
2. \( 0.33 \cdot 10^{-15} \) - This is **not** in scientific notation because the coefficient (0.33) is less than 1.
3. \( 9 \cdot 10^{19} \) - This is in scientific notation (coefficient is between 1 and 10).
4. \( 7.8 \cdot 10^{6} \) - This is in scientific notation (coefficient is between 1 and 10).

The number that is not in scientific notation is **0.33 ⋅ 10−15**.