Math help... Massively stupid here :(

[agnes]

I can't type it as some of the characters are hard to find.

I am confused at how to display both the answer and how I worked it out!

what does the -# mean after the number? How do I work it out?

Beyond confused at the moment Anyone who is great at math please let me know if you are free via msn or something, could use some help.

Any help would be greatly appreciated, I know this is basic stuff but unfortunately math was one of my very weak points throughout school and I NEED to bring it back up to speed.

ags

 

[PhillyDee]

Its MATHS as Mathemetic isn't a word :angry:

You will need a scientific calculator.

 

[jr1104]

There indicies, basically meaning the number times itself that many times. So 10^5 (that's how it's written) would be 10x10x10x10x10, which is equal to 100000. The format you see in the question above is called standard form, which is a way of showing very large and small numbers easily. So 7.23 x 10^5 is 7.23 x 100000, which is 723000.

Hope this helps you see where to go.

 

[agnes]

There indicies, basically meaning the number times itself that many times. So 10^5 (that's how it's written) would be 10x10x10x10x10, which is equal to 100000. The format you see in the question above is called standard form, which is a way of showing very large and small numbers easily. So 7.23 x 10^5 is 7.23 x 100000, which is 723000.

Hope this helps you see where to go.

Great, that clarifies that part, cheers mate, but what about the 10^-3???

I have no idea how that comes into play? Does it reverse it's self into the decimal places? so 10x10x10 (from -3) being 0.010?

ags

 

[Hxc]

10^-1 = 1/10^1
10^-2 = 1/10^2
etc etc

You can do these questions very easily on a calculator by using the E button.

7.23E5 = 7.23 x 10^5

 

[jr1104]

Ah sorry, forgot that bit. The minus just means that it is the inverse (1 over the answer). So 3^-1 would be 1/3, and in your case 10^-3 is 1/(10^3), which is 1/1000.

 

[D D Danneh]

Great, that clarifies that part, cheers mate, but what about the 10^-3???

I have no idea how that comes into play? Does it reverse it's self into the decimal places? so 10x10x10 (from -3) being 0.010?

ags

Yep. 10^-3 is essentially 1/10^3, so the answer is actually 0.001. If it's powers of ten, it's easy to remember, it's simply the number of 0's before/after the one.

Oh, and whenever you multiply/divide powers of the same number, they cancel out which makes them easy, for example, take your above equation:

(7.23 * 10^5 * 1.09 * 10^-3) / (8.97 * 10^-4)

This equation can be rearranged/simplified to 7.23 * 1.09 * 10^5 x 10^-3 / 10^-4 / 8.97

When you multiply 10^5 and 10^-3 together, you simply add the powers, so 5 add -3 is 2, so 10^5 x 10^-3 is 10^2.

When you divide powers, you just subtract the powers, so 10^2 / 10^-4 is 10^6, because 2 minus -4 is 6.

So the final equation simplifies to 7.23 * 1.09 / 8.97 x 10^6

If you calculate 7.23 * 1.09 / 8.97, you get 0.879 (3 d.p)

0.879 x 10^6 is the same as 8.79 x 10^5, so there you go.

 

[agnes]

Brilliant, can anyone show how the paper has come to the get the equation at the bottom which 'should' be the answer?

If I understand correctly, I should be getting this then.

788.07
------------
0.000897

I have a feeling I am going wrong somewhere lol

ags

 

[D D Danneh]

Brilliant, can anyone show how the paper has come to the get the equation at the bottom which 'should' be the answer?

If I understand correctly, I should be getting this then.

788.07
------------
0.000897

I have a feeling I am going wrong somewhere lol

ags

Just edited my above post to show how I worked it out. Your answer is technically correct, if you calculate that, you get 878,561.87

8.79 x 10^5 is 879,000 (essentially 878,561 rounded)

To convert a number into standard form, just multiply or divide the number by a power of 10 so that you have just one number in front of the decimal point - e.g:

878,561.87 / 100,000 = 8.7856187

100,000 is 10^5, round your 8.7856187 to 8.79, and you have 8.79 * 10^5

 

[agnes]

Brilliant, I have the hang of it!

Thank you so much, means a lot

Expect more dumb ass questions soon lol.

ags