Question

Which number is not in scientific notation?

11 ⋅ 1021

5.7 ⋅ 109

3.1 ⋅ 10−12

1.67 ⋅ 10−5

Answer 1

A) 11 x 10^21

Answer 2

A number greater than or equal to 1 but less than 10 is the definition of scientific notation.

The only number on the list that does not fit the definition above is 11•10^21.

Do you see why?

11•10^21 > 1 but not less than 10.

Understand?