Integer Exponents and Scientific Notation: example 10.78

Multiply. Write answers in decimal form: $(4 \times 10^{5}) (2 \times 10^{−7}) .$

Work it out on paper first. Then open the solution one step at a time, and stop as soon as you can finish on your own.

Your turn

The book's Try It right after this example: same idea, new numbers. Only the answer is given.

Multiply. Write answers in decimal form: $(3 \times 10^{6}) (2 \times 10^{−8}) .$

How did it go?

	$(4 \times 10^{5}) (2 \times 10^{−7})$
Use the Commutative Property to rearrange the factors.	$4 \cdot 2 \cdot 10^{5} \cdot 10^{−7}$
Multiply 4 by 2 and use the Product Property to multiply $10^{5}$ by $10^{−7}$ .	$8 \times 10^{−2}$
Change to decimal form by moving the decimal two places left.	$0.08$

	$(4 \times 10^{5}) (2 \times 10^{−7})$
Use the Commutative Property to rearrange the factors.	$4 \cdot 2 \cdot 10^{5} \cdot 10^{−7}$
Multiply 4 by 2 and use the Product Property to multiply $10^{5}$ by $10^{−7}$ .	$8 \times 10^{−2}$
Change to decimal form by moving the decimal two places left.	$0.08$