scientific notation operations and word problems

The mean distance from the sun to Earth is 9.29 x 10⁷ miles. Jupiter's mean distance from the sun is 4.8388 x 10⁸ miles. What is the difference between these two distances in miles? 

• 4.3092 x 10¹
• 3.9098 x 10⁷
• 3.9098 x 10⁸
• 5.7678 x 10⁸

A microgram is equal to 1 x 10 ^-6 grams. How many times greater than a microgram is 1 x 10² grams? 

• 1 x 10^-8
• 1 x 10^-4
• 1 x 10⁴
• 1 x 10⁸

The Diplodocus dinosaur is believed to have become extinct approximately 1.38x10⁸ years ago.  The Oviraptor is believed to have become extinct approximately 7x10⁷ years ago.  How many years were there between the extinction of these two dinosaur types?

• 6.8 x 10⁸
• 6.8 x 10⁹
• 68 x 10⁸
• 6.8 x 10⁷

A computer's hard disk drive holds 8 x 10⁷ bytes of information.  If Jill buys an extra memory stick that holds 3 x 10⁶ bytes of information, how much memory will the computer hold?

• 11 x 10¹³
• 11 x 10⁷
• 8.3 x 10¹³
• 8.3 x 10⁷

Simplify: $\left(7.5\times10^3\right)\left(1.8\times10^5\right)$  

•  $13.5\times10^8$  

•  $13.5\times10^9$  

•  $1.35\times10^9$  

•  $9.3\times10^8$  

Michigan has an area of  $9.6\times10^4$  square miles and California has an area of  $1.6\times10^5$  square miles. What is the difference of the two areas?

•  $.64\times10^4$  

•  $6.4\times10^4$  

•  $7\times10^5$  

•  $.64\times10^5$  

Simplify:  $\left(6.8\times10^{-3}\right)+\left(1.2\times10^{-2}\right)$  

•  $8.16\times10^{-3}$  

•  $5\times10^2$  

•  $1.88\times10^{-3}$  

•  $1.88\times10^{-2}$  

The distance from China to Europe is  $6.7\times10^3$ miles and the distance from China to America is  $1.1\times10^4$  miles. What is the difference of the two distances?

•  $4.3\times10^3$  

•  $.43\times10^3$  

•  $.43\times10^2$  

•  $7.8\times10^4$  

Simplify:  $\frac{\left(7.2\times10^5\right)}{1.3\times10^{ }}$  

•  $5.538\times10^5$  

•  $5.538\times10^4$  

•  $5.9\times10^4$  

•  $5.9\times10^3$  

Solve:
(2.1×10​²​​) × (3.0×10​⁴)

• 5.1 x 10²
• 6.3 x 10⁶
• 5.1 x 10⁶
• 6.3 x 10⁸