Help with this math problem... I'm not smarter than a 5th grader

[Anonymous]

Ok, I hate that I'm asking this... but the kid got it wrong and I see what the right answer is supposed to be, but I don't understand.

3^3 - 6(10-8) + 5

Please tell me what you think the answer is.

I thought it was 9 - (12) + 5 = 2.

Apparently that is not right.

[Anonymous]

3^3 is 27, not 9.

[Anonymous]

Anonymous wrote:Ok, I hate that I'm asking this... but the kid got it wrong and I see what the right answer is supposed to be, but I don't understand.

3^3 - 6(10-8) + 5

Please tell me what you think the answer is.

I thought it was 9 - (12) + 5 = 2.

Apparently that is not right.

Is 3^3 = 3 exponent 3 ? I so, the answer is not 9. It is 27 = 3 * 3 * 3.

[Anonymous]

PEMDAS.

Parentheses=

27 - 6(2) + 5

27 - 12 + 5

Then I think you just do it in order now ...

15+5=20

[Anonymous]

Thank you! ... but I need more help b/c the answer in the on-line test says it's "10"

So, even using 27, that would make the answer 22. So what?????

[Anonymous]

Now I'm really mixing up my numbers in my head -- yes, 20:39, you have it the way I should have had it.... but that's still not "10"...???

[Anonymous]

They got ten by doing the addition first, then the subtraction, at my last step.

So 27-17 is 10.

I am a middle school science teacher. I thought with PEMDAS, When it comes to MD and AS, you do them in order. So the subtracting 27-12 would come before the adding 12+5. The online answe does not agree with me. I guess I could be wrong. That's just how I remember doing it. Granted, I havent gone over this in a long time!

[Anonymous]

The answer is 20.

Are you sure it's +5 at the end and not -5. If it was -5, that would make the answer 10.

[Anonymous]

3^3 - 6(10-8) + 5

27-6(2)+5

27-12+5

15+5

20

What on-line test are you looking at?

[Anonymous]

Anonymous wrote:They got ten by doing the addition first, then the subtraction, at my last step.

So 27-17 is 10.

I am a middle school science teacher. I thought with PEMDAS, When it comes to MD and AS, you do them in order. So the subtracting 27-12 would come before the adding 12+5. The online answe does not agree with me. I guess I could be wrong. That's just how I remember doing it. Granted, I havent gone over this in a long time!

Yes, you do multiplication/division in order from left to right, and then you do addition/subtraction in order from left to right. It really ought to be

P
E
M/D
A/S

[Anonymous]

Anonymous wrote:3^3 - 6(10-8) + 5

27-6(2)+5

27-12+5

15+5

20

What on-line test are you looking at?

It's an online test that FCPS uses.

[Anonymous]

So the online test FCPS uses is wrong?

[Anonymous]

3^3-6(10-8)+5

27-(60-48)+5

27-12+5

27-17=10

Using PEMDAS: Parentheses, Exponent, Mulplication, Division, Addition, Subtraction.

Do it in this order.

[Anonymous]

Anonymous wrote:3^3-6(10-8)+5

27-(60-48)+5

27-12+5

27-17=10

Using PEMDAS: Parentheses, Exponent, Mulplication, Division, Addition, Subtraction.

Do it in this order.

Except multiplication and division are "equal" in priority, as are addition and subtraction. The answer is 20, not 10.

I'm really dreading elementary school math now.

[Anonymous]

the answer IS 20