[G-Daddy_Peaches]

23. Express the following numbers in scientific notation: 6500, 0.00630, 860 (assume this number is measured to + 10), 860 (assume this number is measured to + 1), 186,000, 0.10010.
25. Which of the following are likely to be exact numbers? Why? 554in, 7 computers, $20,355.47, 25lbs sugar, 12.5 gal of diesel fuel, 5446 ants.
 Need help with these two...

[Borek]

23. Express the following numbers in scientific notation: 6500, 0.00630, 860 (assume this number is measured to + 10), 860 (assume this number is measured to + 1), 186,000, 0.10010.
25. Which of the following are likely to be exact numbers? Why? 554in, 7 computers, $20,355.47, 25lbs sugar, 12.5 gal of diesel fuel, 5446 ants.

You have to show your attempts at solving the question to receive help. This is a forum policy.

[Arkcon]

Well, there's actually 12 individual questions in this set. Can you begin to try some of them, so we can see where you need help?  That's part of the Forum Rules{click}

[G-Daddy_Peaches]

23. Express the following numbers in scientific notation: 6500, 0.00630, 860 (assume this number is measured to + 10), 860 (assume this number is measured to + 1), 186,000, 0.10010.   6.5 * 10^3 , 6.3 * 10^-3 , 86*10^1, 8.6*10^2, 1.86*10^5, 1.001*10^-1
25. Which of the following are likely to be exact numbers? Why? 554in, 7 computers, $20,355.47, 25lbs sugar, 12.5 gal of diesel fuel, 5446 ants.
7 Computers, because these are definite items and cannot have increments
$20,355.47 Because this number seems fairly large and money may be rouded but is definite.


Not sure what the assume number is measured in 23 means and what they mean by exact numbers

[Arkcon]

Your textbook may have a useful definition for what they want you to think of when they say "exact numbers,"  there are many possible definitions.  Maybe if you start with some textbook examples, you can see what you have to do.

[G-Daddy_Peaches]

The questions were given in a lecture in note form and there is no textbook as I am aware.

[fledarmus]

One easy way to look at exact numbers: think about a situation where you would be measuring this number, imagine that you mis-measured the number by a fraction, and see if the term makes sense in that context.

 > 554 inches - could you see being off by half an inch?
 > 7 computers - could you imagine being off by half a computer?
 > $20,355.47 - if this was the price of a new car, say, could you imagine being off by half a cent?
 > 25 lbs suger - could you imagine being off by half a pound?
 > 12.5 gal of diesel fuel - could you imagine being off by 0.01 gallons?
 > 5446 ants - could you imagine being off by half an ant?

If the answer is "no, it would have to be off by at least a whole unit rather than a fraction..." then it is an exact number.

You still haven't made a start on the scientific notation question, so I'll leave you to work on that one or ask a more specific question.

[Borek]

You still haven't made a start on the scientific notation question, so I'll leave you to work on that one or ask a more specific question.

Actually he did.

6.5 * 10^3 , 6.3 * 10^-3 , 86*10^1, 8.6*10^2, 1.86*10^5, 1.001*10^-1

First one is OK. Next to the last is IMHO OK as well. All others look wrong to me.

[fledarmus]

Ah, missed that - thanks Borek!