Decimals and Square roots?

[Loheil]

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I'm just having some problems with decimals and square roots and even dividing decimals. Does anyone have some helpful knowledge or clever tricks I can use to make this process easier?

Also, do we get a simple calculator on the DAT or no calculator at all? On the free kaplan test I was able to use a calculator at some point I think.

Anyways, here's just an example of a decimal square root that I don't know how to do without a calculator.

Square root of (1 x 10^-5) = (3.2 x 10^-3).

Thanks

 

[Sandstorm]

I'm just having some problems with decimals and square roots and even dividing decimals. Does anyone have some helpful knowledge or clever tricks I can use to make this process easier?

Also, do we get a simple calculator on the DAT or no calculator at all? On the free kaplan test I was able to use a calculator at some point I think.

Anyways, here's just an example of a decimal square root that I don't know how to do without a calculator.

Square root of (1 x 10^-5) = (3.2 x 10^-3).

Thanks

Put everything in scientific notation. In your example the square root is (1 x 10^-5) ^1/2.

Rearrange this to (10 x 10^-6) ^ 1/2

Then you have (10) ^ 1/2 x (10^-6)^1/2

3 squared is 9, 4 squared is 16, so your first term should be between 3 and 4, closer to 3.

Your second term is then 10^-3

 

[Sandstorm]

It's a multiple choice test so this should get you close rnough

 

[robboyle10]

Simple calculator, but it is a pain in the ass to use because you are unable to use the keyboard (must click all of the buttons).

As far as decimals go, either use the calculator or switch everything to scientific notation. Much easier for multiplying and dividing.

Ex. .006 x .0002 (6x10^-3 x 2x10^-4)....all you have to do is multiply 6x2 and then add their exponents....12x10^-7 or 1.2x10^-6. If you are dividing the numbers you would do the same thing except you would divide (6/2) and subtract the exponents (-3-(-4)). ***It is important to be efficient with scientific notation and exponential rules for acid/base problems since you do not get a calculator in the sciences section.

For square roots, it is important to know your basics. If you are taking the square of something you will take half of the exponent (take 1/3 for cube root...and so on). In your example I would switch 1x10^-5 to 10x10^-6. Since the sq rt of 9 is 3, the sq rt of ten would be just a little more than that. So I know the answer would be ~3x10^-3. The exam is multiple choice so you just need to find answers that are close.

Hope that helps.

 

[robboyle10]

Ha. Beat me to it! Thanks Sandstorm.

 

[Loheil]

Thanks guys for your help.