Standard Form：练习题

Express \( 0.000042 \) in standard form.

The thickness of a piece of paper is \( 9.5 \times 10^{-3} \text{ cm} \). What is the total thickness of \( 2000 \) pieces of such paper, expressed in standard form?

Calculate \( (4.2 \times 10^5) + (3.1 \times 10^5) \) and express the answer in standard form.

Express the product of \( 5 \times 10^6 \) and \( 3 \times 10^{-2} \) in standard form.

Express \( 0.0000000352 \) in standard form.

The distance between two planets is approximately \( 1.5 \times 10^8 \text{ km} \). Express this distance in ordinary notation.