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Daughter's math homework (1 Viewer)

MrPack

reformed delinquent
Maybe I'm :bag: but here goe.......

Solve this problem:

-5² + 4 x 2³ =

-6² + 2 x 3² =

My answers57 and 54

 
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Smoo

Fear the Beaver
Maybe I'm :bag: but here goe.......

Solve this problem:

-5² + 4 x 2³ =

-6² + 2 x 3² =

My answers57 and 54
1. 572. 54

Order of operations. First resolve the exponents, then the multiplication, then the addition.

 
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Smoo

Fear the Beaver
1st one = 7

2nd one = -18
depends if you look at as -(5^2) or (-5)^2. I assume the latter, but could be wrong.
No, I think bryhamm's right. Unless it's specifically (-5)^2 then "-5^2" is -25, not 25. I think the teacher is right.There was a thread about this before. I think Shick! cleared it all up.

 

Caesar

Footballguy
Maybe I'm  :bag:   but here goe.......

Solve this problem:

-5² + 4 x 2³ =

-6² + 2 x 3² =

My answers57 and 54
no parentesis??? could be 1. 232 or 57 I think 57.. I was always taught mult/div takes precedence over add/sub

2. 342 or 54 I say 54

 
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Brewdude

Footballguy
#1 - 57#2 - 54A negative number raised to an even power makes a positive number. Raised to an odd power is a negative number.What's the teacher saying?

 

bryhamm

Footballguy
Maybe I'm  :bag:   but here goe.......

Solve this problem:

-5² + 4 x 2³ =

-6² + 2 x 3² =

My answers57 and 54
1. 572. 54

Order of operations. First resolve the exponents, then the multiplication, then the addition.
-5² + 4 x 2³ = 25 + 32 = 57

-6² + 2 x 3² = 36 + 18 = 54
You do the exponentials first, and since there is not a parenthesis around the 5 in the first one or the 6 in the 2nd one, you end up with -25 and -36 respectively.Had they wanted 25 and 36, then it should have been written (-5)² and (-6)²

 

MrPack

reformed delinquent
1) 57

2) 54

Parentheses

Exponents

Multiplication

Division

Addition

Subdtraction

you're done
This is exactly how my daughter worked it. The teacher marked them both wrong.
 

Smoo

Fear the Beaver
#1 - 57

#2 - 54

A negative number raised to an even power makes a positive number. Raised to an odd power is a negative number.

What's the teacher saying?
It's a positive number being raised to a power, and then negated. The minus sign is the same as multiplying by -1, and thus isn't done until the multiplication step in the order of operations.
 

MrPack

reformed delinquent
1st one = 7

2nd one = -18
depends if you look at as -(5^2) or (-5)^2. I assume the latter, but could be wrong.
No, I think bryhamm's right. Unless it's specifically (-5)^2 then "-5^2" is -25, not 25. I think the teacher is right.There was a thread about this before. I think Shick! cleared it all up.
-5² should = -25 right? It's a negative x negative
 

Nathan R. Jessep

That Hug Life
maybe it's just me, but I read that aloud as "negative 5 squared"...since when do negative numbers HAVE to be surrounded by parentheses?

 

MrPack

reformed delinquent
#1 - 57

#2 - 54

A negative number raised to an even power makes a positive number. Raised to an odd power is a negative number.

What's the teacher saying?
Teacher says 7 and -18
 

rolyaTy

You're Heinous
1) 57

2) 54

Parentheses

Exponents

Multiplication

Division

Addition

Subdtraction

you're done
This is exactly how my daughter worked it. The teacher marked them both wrong.
The teacher is right.(-5)^2 != -5^2 because the latter is -(5^2). Order of operations.

 

Smoo

Fear the Beaver
1st one = 7

2nd one = -18
depends if you look at as -(5^2) or (-5)^2. I assume the latter, but could be wrong.
No, I think bryhamm's right. Unless it's specifically (-5)^2 then "-5^2" is -25, not 25. I think the teacher is right.There was a thread about this before. I think Shick! cleared it all up.
-5² should = -25 right? It's a negative x negative
No. New math says to think of "-5" as "5 x (-1)". So when you see "-5^2", you're actually seeing "-1 x 5^2".I know that's different from how we did it, but it seems to be the way it's being done these days.

 

Brewdude

Footballguy
Maybe I'm  :bag:   but here goe.......

Solve this problem:

-5² + 4 x 2³ =

-6² + 2 x 3² =

My answers57 and 54
1. 572. 54

Order of operations. First resolve the exponents, then the multiplication, then the addition.
-5² + 4 x 2³ = 25 + 32 = 57

-6² + 2 x 3² = 36 + 18 = 54
You do the exponentials first, and since there is not a parenthesis around the 5 in the first one or the 6 in the 2nd one, you end up with -25 and -36 respectively.Had they wanted 25 and 36, then it should have been written (-5)² and (-6)²
WTF? I don't remember this rule...doesn't make sense. The "-" is not a stand-alone operator...it must be combined with the number to make any sense.You can't compute the number and leave the "-" out there by itself, then throw it back in later.

That's like saying 12^2 is 14 (drop off the 1, compute the 2, add the one back in).

The number being computed is -5, not 5.

 

Smoo

Fear the Beaver
maybe it's just me, but I read that aloud as "negative 5 squared"...since when do negative numbers HAVE to be surrounded by parentheses?
Yes, but that can still be read two ways. Negative...5 squared or negative 5...squared.
 

Brewdude

Footballguy
1st one = 7

2nd one = -18
depends if you look at as -(5^2) or (-5)^2. I assume the latter, but could be wrong.
No, I think bryhamm's right. Unless it's specifically (-5)^2 then "-5^2" is -25, not 25. I think the teacher is right.There was a thread about this before. I think Shick! cleared it all up.
-5² should = -25 right? It's a negative x negative
negative * negative = positivenegative * negative * negative = negative

 

Smoo

Fear the Beaver
maybe it's just me, but I read that aloud as "negative 5 squared"...since when do negative numbers HAVE to be surrounded by parentheses?
Yes, but that can still be read two ways. Negative...5 squared or negative 5...squared.
:doh: negative 5, squared
Right, but it's now being done such that the way it is written is to be read as negative, 5 squared.
 

MrPack

reformed delinquent
1st one = 7

2nd one = -18
depends if you look at as -(5^2) or (-5)^2. I assume the latter, but could be wrong.
No, I think bryhamm's right. Unless it's specifically (-5)^2 then "-5^2" is -25, not 25. I think the teacher is right.There was a thread about this before. I think Shick! cleared it all up.
-5² should = -25 right? It's a negative x negative
No. New math says to think of "-5" as "5 x (-1)". So when you see "-5^2", you're actually seeing "-1 x 5^2".I know that's different from how we did it, but it seems to be the way it's being done these days.
Wow, I'll say it's different. And I used to be good in math. :bag: I will have to explain to her the bolded part. It certainly makes it a bit easier to understand.

 

rolyaTy

You're Heinous
It's an order of operations thing.(-5)^2 is said as "Negative five squared"-5^2 is said as "The negative of five squared" and as such, you square it first and then negate.

 

KTM

Braaaaaaaaaap
1st one = 7

2nd one = -18
:goodposting: -5² + 4 x 2³ =

-6² + 2 x 3² =

(1)

5 x 5 =25 x -1 = -25

2x2x2 = 8

4x8 = 32

-25 + 32 = 7

(2)

6x6 = 36 x -1 = -36

3x3 = 9

2x9 = 18

-36+18 = -18

 

Caesar

Footballguy
1st one = 7

2nd one = -18
depends if you look at as -(5^2) or (-5)^2. I assume the latter, but could be wrong.
No, I think bryhamm's right. Unless it's specifically (-5)^2 then "-5^2" is -25, not 25. I think the teacher is right.There was a thread about this before. I think Shick! cleared it all up.
-5² should = -25 right? It's a negative x negative
negative * negative = positivenegative * negative * negative = negative
All this negativity is making me depressed... I'm out
 

Smoo

Fear the Beaver
It's an order of operations thing.

(-5)^2 is said as "Negative five squared"

-5^2 is said as "The negative of five squared" and as such, you square it first and then negate.
Yes. We've established that that's the right answer today. Do you remember, though, that that was not taught that way back when we were in school?
 

rolyaTy

You're Heinous
It's basically done out of necessity.You can write something 3 ways:-5^2(-5)^2-(5)^2For clarities sake, -5^2 is defined as -(5)^2, it's just a rule and it's been that way since I was little.

 

MrPack

reformed delinquent
I put these equations in a scientific calculator and still came up with 75 and 54. -5² came out as 25, not -25.This is frigging nuts

 

Brewdude

Footballguy
To get 7 & 18 as answers, the equations should have been written:-(5^2) + 4 X 2^3and-(6^2) + 2 X 3^2At least this is what I recall from my math classes. Why change something like this for "new" math?

 

Smoo

Fear the Beaver
It's basically done out of necessity.

You can write something 3 ways:

-5^2

(-5)^2

-(5)^2

For clarities sake, -5^2 is defined as -(5)^2, it's just a rule and it's been that way since I was little.
It was most definitely not that way when I went to school. How old are you?
 

rolyaTy

You're Heinous
It's an order of operations thing.

(-5)^2 is said as "Negative five squared"

-5^2 is said as "The negative of five squared" and as such, you square it first and then negate.
Yes. We've established that that's the right answer today. Do you remember, though, that that was not taught that way back when we were in school?
It's been like that as far back as I can remember. Course, I was taught this stuff in the 80's...dunno how far back y'all go. It's just one of those cooky definitions you have to have drilled in your head, that makes little logical sense but is necessary later on in math, like the order of operations.
 

MrPack

reformed delinquent
It's basically done out of necessity.

You can write something 3 ways:

-5^2

(-5)^2

-(5)^2

For clarities sake, -5^2 is defined as -(5)^2, it's just a rule and it's been that way since I was little.
It was most definitely not that way when I went to school. How old are you?
:goodposting: I was taught like this:

Brewdude Posted Today, 05:45 PM

To get 7 & 18 as answers, the equations should have been written:

-(5^2) + 4 X 2^3

and

-(6^2) + 2 X 3^2

At least this is what I recall from my math classes. Why change something like this for "new" math?
 

tommyboy

Footballguy
if they want a negative square they should have written the question as-(5^2)which would be -25if you write -5^2 = -5 x -5 = +25the teacher is motarded

 

Smoo

Fear the Beaver
So MrPack, Bewdude and I were all taught the same way, and we're decidedly not from the same geographic area. So I don't know where roly went to school, but he's either much younger, or his district was way ahead of its time.

 

rolyaTy

You're Heinous
Yeah, as someone said earlier I think they take the negative sign as a multiplicaiton of (-1) times a number. So:-5^2 really is (-1)x(5)^2 whereas (-5)^2 is (-1x5)^2 :shrug:

 
Yeah, as someone said earlier I think they take the negative sign as a multiplicaiton of (-1) times a number. So:

-5^2 really is (-1)x(5)^2 whereas (-5)^2 is (-1x5)^2 :shrug:
I was taught to do -5^2 as 25 because of no parethesis. If parenthesis then it would be negative because the negative is outside the rules of doing exponents first. I was taught in the mid 90's though. Dont know if I am in your group or rolyaTy's.
 

Bevo

Footballguy
IIRC, I was taught this stuff in the early to mid 60s. The way I was taught was that -5^2 == -25

 

chet

Footballguy
IIRC, I was taught this stuff in the early to mid 60s. The way I was taught was that -5^2 == -25
\/\/o\/\/Math in the sixties must have been psychadelic with all those double equals signs. :banned:

 

Smoo

Fear the Beaver
IIRC, I was taught this stuff in the early to mid 60s. The way I was taught was that -5^2 == -25
This is weird. Is this old math then?I would have learned this in the early '80s (what grade do they do this in? 5? 6?) and I was taught that -5^2 == +25.

 

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