Estimating in Scientific Notation

Express the following in scientific notation:
.000457

• 457 x 10^6

• 457 x 10^-6

• 4.57 x10^4

• 4.57 x 10^-4

8.3 x 10³

• 83

• 8,300

• 0.0083

• 830

Write the following number in scientific notation:

.0004

Which is the smallest?
1.3 x 10²⁰
2.9 x 10²¹
9.5 x 10³²
8.4 x 10¹⁹

• 1.3 x 10²⁰

• 2.9 x 10²¹

• 9.5 x 10³²

• 8.4 x 10¹⁹

What can (2.5 x 10^8) be estimated as for easier comparison in scientific notation?

• (2 x 10^8)

• (3 x 10^8)

• (2.5 x 10^7)

• (3 x 10^9)

A bacteria cell has a diameter of .00031 cm. Which expression is the best estimate for the diameter of the bacteria cell?

The diameter of a speck of dust is about 0.00002 inches. Which of these is an appropriate estimate for the diameter of the speck of dust?

• 2 × 10^–5 in.

• 2 × 10^–4 in.

• 2 × 10⁵ in.

Which of the following would be a reasonable estimate for the weight of a pencil?

• 1x10^-20 lb

• 1x10² lb

• 1x10²⁰ lb

• 1x10^-2 lb

3.9 x 10⁸

• 390000000.

• 39000

Express in standard form.

• A

• B

• C

• D