Eric M. answered • 03/10/15
Tutor
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Chemistry, Mathematics, Physical Sciences, Writing...take your pick!
Hello Anne,
These questions are pretty basic, so I think you need to review what scientific notation is and how it works. Look at question 1, which tells you the accepted form for a number in scientific notation.
A question you might ask is "why use scientific notation?" The reason is that significant figures are easier to identify. For example, how many significant figures are there in the number 22,100,000? Three? But what if I gave it to you in scientific notation as 2.210*107? Now you know that the first 0 is significant, and the number has four significant figures, not 3.
Scientific notation also makes calculations much easier, as you can do the exponential parts in your head and just work with the coefficients (first factors) on your calculator. For example, try calculating 0.00007 * 126,000,000/10,240. It's easy to add an extra zero or leave one out. But if you calculate it as (7*10-5)*(1.26*108)/(1.024*104), you know the power of 10 to use is -5 + 8 + 4 = 7. The first factors are 7*1.26/1.024 = 8.6. Since this is between 1 and 10, you're done. The answer is 8.6*107.
Learn to love scientific notation -- you'll be glad you did. (That sounds like an ad, but it's true.)
As to your questions:
1. A (assuming "10-8" means "10-8")
2.B, D, C, A.
3. D
Regards,
Eric Moline
McMinnville OR
