1. ## 8th Grade ... Pre Algebra ... HELP!

I have a math test tomorrow and idk how 2 do sum stuff.
im having trouble with how to:
Evaluate decimal numbers with a positive power
Evaluate decimal numbers with a negative power
Evaluate negative numbers with positive exponents
Evaluate negative numbers with negative exponents

I litterally skipped 2 grades worth of math. I skipped anything I would have learned in 6th and 7th grade math . unfortunately, thats mostly what i need 2 be able 2 do this. I would luv if someone could SIMPLY xplain 2 me how to do these.
Thx so much,
Clueless

2. Originally Posted by tatsing11
I have a math test tomorrow and idk how 2 do sum stuff.
im having trouble with how to:
Evaluate decimal numbers with a positive power
Evaluate decimal numbers with a negative power
Evaluate negative numbers with positive exponents
Evaluate negative numbers with negative exponents

I litterally skipped 2 grades worth of math. I skipped anything I would have learned in 6th and 7th grade math . unfortunately, thats mostly what i need 2 be able 2 do this. I would luv if someone could SIMPLY xplain 2 me how to do these.
Thx so much,
Clueless
when you say "evaluate" what to you mean?

can't you just plug them into a calculator, or do you have to work them out by hand? do you know what raising a number to a positive power does? what about a negative power?

3. ## Evaluation

by evaluate, i mean figure out the value of the number. such as this prob:
Evaluate: 32 would be 9. thats what our math teachr says so yep and um
im okay with positive numbers with negative powers and stuff but i have no idea about decimals or neg numbrs and neg powers

4. Originally Posted by tatsing11
by evaluate, i mean figure out the value of the number. such as this prob:
Evaluate: 32 would be 9. thats what our math teachr says so yep and um
im okay with positive numbers with negative powers and stuff but i have no idea about decimals or neg numbrs and neg powers

well, i am trying to get at what level of sophistication you require, but you are not telling me much

all i can say is that you treat the decimals just as you would whole numbers

example, $\displaystyle 3.02^2 = 3.02 \times 3.02 = 9.1204$

or, $\displaystyle 3.02^3 = 3.02 \times 3.02 \times 3.02 = 27.543608$

etc

if you have $\displaystyle 3.02^{-2} = \frac 1{3.02^2} = \frac 1{9.1204} = 0.1096 \dots$

5. ## srry

srry dude but i need an xplanation stilll. im only in 6th grde but im in 8th grade math so i stll dk how 2 do it

6. let me try to make this easier:

power means multiplying by it self
"to the power of" is often replace by ^

ex. 3 "to the power of" 4
3 ^ 4
3 multiplies by it self 4 times = 3x3x3x3 = 81

ok here are some rules you just have to memorize

1. if you have a negative number and you take the power of a odd number you will end up with a negative number

(-3) ^ 3 = (-3)x(-3)x(-3) = -27

2. if you have a negative number and you take the power of a even number you will end up with a positive number
3 ^ 4 = 3x3x3x3x = 81

3. when you take it to the power of a negative number, basicly just treat the minus sign as 1 over "the number"
3 ^ (-2) = 1 over 3^2 = 1/3 x 1/3 = 1/9

7. Also, evaluating a number to a fractional power involves taking roots. For instance, $\displaystyle 3^{1.5} = 3\sqrt{3}$.

8. Hi well you see if you are haveing problems with this just do what i do talk to the teacher and ask if you can study more befor you take the tes or you can just ask to retake the test me my self have a test to take next class to day and it is all about this stuff i know all of it so im shour i gunna get an A

9. ## plz help

can any one help me with a problem like this

5 to the 6th power times 6 to the 5th power divided by 9 to the 3 power

my teacher said if we can simplfie it and figer it out we get NO HOMEWORK FOR THE REST OF THE YEAR

10. well this is my last post i might talk to you guys later i guess Bye

11. Originally Posted by tatsing11
srry dude but i need an xplanation stilll. im only in 6th grde but im in 8th grade math so i stll dk how 2 do it
Sounds like you need some serious help in writing in plain English!

12. Originally Posted by sandgaara
can any one help me with a problem like this

5 to the 6th power times 6 to the 5th power divided by 9 to the 3 power

my teacher said if we can simplfie it and figer it out we get NO HOMEWORK FOR THE REST OF THE YEAR
well that's not fair.

by the way, post new questions in a new thread.

i will start you off though, you finish up. start by writing 6 as 3*2 and writing 9 as 3^2