OT: Simple Math Question

[yesrutgers01]

OK, so, my Niece is staying with us for a while and taking pre algebra - She has a number of fraction equations to do and when she does them, it just isn't computing in my old mind and she can't walk through the steps and seems she is just giving answers she was giving- BTW- her teachers are doing that a lot. Giving quizzes and answers

-3 2/7 divided by 1 1/4 = 23/798

Is this actually the correct answer and how do you get to that answer?

 

[Tango Two]

OK, so, my Niece is staying with us for a while and taking pre algebra - She has a number of fraction equations to do and when she does them, it just isn't computing in my old mind and she can't walk through the steps and seems she is just giving answers she was giving- BTW- her teachers are doing that a lot. Giving quizzes and answers

-3 2/7 divided by 1 1/4 = 23/798

Is this actually the correct answer and how do you get to that answer?

I think this is it:

Convert to decimal

-3 2/7 divided by 1 1/4 =

2/7 = .2857

1/4 = .25

-3.2857 / 1.25 = -2.6285

 

[hoquat63]

Division of fractions
1 convert whole number to a fraction
2 invert and multiply
(Is that a dash or a minus sign in front, of a minus your answer should me a minus)
Will sit down and get pencil and paper to do calculation. Let you know in a couple of minutes.

 

[BigWill]

Does new math teach addition/subtraction/multiply/division ?

 

[CJ1987]

I get -92/77, I'll try to explain:

-3 2/7 equals -23/7

-23/7 divided by 11/4 OR -23/7 times 4/11

multiply across numerator and denominator I get -92/77, not sure if it's right

 

[hoquat63]

Division of fractions
1 convert whole number to a fraction
2 invert and multiply
(Is that a dash or a minus sign in front, of a minus your answer should me a minus)
Will sit down and get pencil and paper to do calculation. Let you know in a couple of minutes.

3 2/7 =23/7, 1 1/4=5/4
So 23/7 x 4/5 = 92/35

 

[OldManRiver1]

My head's hurting...now back to drinking

 

[red sail]

- 3 2/7 = Negative 3= -(21/7 + 2/7) = -23/7
1 1/4 = 4/4 + 1/4 = 5/4

-23/7 Divided 5/4 = -23/7 x 4/5 = (forgot the Negative sign) -92/35

 

[yesrutgers01]

it is a minus 3 2/7

 

[BigWill]

prove it

 

[yesrutgers01]

3 2/7 =23/7, 1 1/4=5/4
So 23/7 x 4/5 = 92/35

- 3 2/7 = Negative 3= 21/7 + 2/7 = 23/7
1 1/4 = 4/4 + 1/4 = 5/4

23/7 Divided 5/4 = 23/7 x 4/5 = 92/35

Would that actually make it negative 21/7 plus 2/7 = negative 19/7

 

[CJ1987]

- 3 2/7 = Negative 3= 21/7 + 2/7 = 23/7
1 1/4 = 4/4 + 1/4 = 5/4

23/7 Divided 5/4 = 23/7 x 4/5 = 92/35

11/4 cannot equal 5/4

I think my math is correct but I may have screwed up the positive and negative

 

[RC_2002]

11/4 cannot equal 5/4

I think my math is correct but I may have screwed up the positive and negative

it is not 11/4 it is One and 1/4 i think --> 5/4

 

[red sail]

11/4 cannot equal 5/4

I think my math is correct but I may have screwed up the positive and negative

I may be wrong but I read that as 1 1/4 (one and a quarter). its probably been 30 years since i've had algebra and my kids would know the answer right away but I think my math is right

 

[CJ1987]

wow, my bad, I thought it was 11/4 not 1 and 1/4.......now I have to redo all my work, oh well.

 

[ScarletR97*]

I think this is it:

Convert to decimal

-3 2/7 divided by 1 1/4 =

2/7 = .2857

1/4 = .25

-3.2857 / 1.25 = -2.6285

You are correct and in fraction it would be - 2 5/8. I did the math and agree with you and for the heck of it I asked my Google Assistant and she had the same answer as well.

 

[yesrutgers01]

I just went through her assignments better and see they gave her an example and it follows your steps
since the fist number is a negative, I am thinking it may be
-3 2/7 divided by 1 ¼

Negative 3 = negative 21/7 + 2/7 = negative 23/7

1 ¼ = 4/4 + ¼ = 5/4

-23/7 divided by 5/4 =

-23/7 x 4/5

-92/35

 

[lne001]

Here is my attempt.

1) Find common denominator -92/28 divided by 77/28
2) Invert and multiply -92/28 times 28/77 = -2576/2156
3) Simplify fraction -1 105/539

The answer must be approximately -1 and a fraction since -3+ divided by 2+ = -1 and a fraction, so this answer appears to be in the ballpark at least.

Not bad, I think, for a 1969 RC poli sci major.

 

[yesrutgers01]

Here is my attempt.

1) Find common denominator -92/28 divided by 77/28
2) Invert and multiply -92/28 times 28/77 = -2576/2156
3) Simplify fraction -1 105/539

The answer must be approximately -1 and a fraction since -3+ divided by 2+ = -1 and a fraction, so this answer appears to be in the ballpark at least.

Not bad, I think, for a 1969 RC poli sci major.

that was the direction I originally thought with finding the common denominator but she was telling me they dont learn that way...
And she is lazy...I am working harder on this than she is.

I have been listening to her teachers online as I now have to share my office with her and they really just give out answers...It seems more like teachers wanting to have a class full of good grades rather than really teach and make sure the students understand how to get the answer. Catching the damn fish for them...

 

[RutHut_rivals]

Dude, I know you use this board because you're too lazy to do research on your next vehicle or where you might want to move. But now 4th grade math? C'mon man!

 

[yesrutgers01]

Dude, I know you use this board because you're too lazy to do research on your next vehicle or where you might want to move. But now 4th grade math? C'mon man!

hey, the board has actually been a wealth of knowledge. I lean toward experience rather than what I read.

I do have to laugh a little though...we are all experienced, mostly college educated and 4th grade math has us not 100% sure of our answers. lol And it is 7th grade math hahahaha

 

[lne001]

that was the direction I originally thought with finding the common denominator but she was telling me they dont learn that way...

While they may not learn that way, there is only one correct answer to that problem, and it is not 23/798.

 

[yesrutgers01]

While they may not learn that way, there is only one correct answer to that problem, and it is not 23/798.

So true

 

[Tango Two]

I think this is it:

Convert to decimal

-3 2/7 divided by 1 1/4 =

2/7 = .2857

1/4 = .25

-3.2857 / 1.25 = -2.6285

You are correct and in fraction it would be - 2 5/8. I did the math and agree with you and for the heck of it I asked my Google Assistant and she had the same answer as well.

Thanks

 

[lne001]

Ignore all my comments. My old eyes misread -1 1/4 as -11/4, and I'm not going back to recalculate.

 

[ashokan]

My slysdexia is acting up

 

[RobotHunter]

Here is my attempt.

1) Find common denominator -92/28 divided by 77/28
2) Invert and multiply -92/28 times 28/77 = -2576/2156
3) Simplify fraction -1 105/539

The answer must be approximately -1 and a fraction since -3+ divided by 2+ = -1 and a fraction, so this answer appears to be in the ballpark at least.

Not bad, I think, for a 1969 RC poli sci major.

You don't need a common denominator to divide fractions only to add and subtract.

 

[fsg2_rivals]

Division of fractions
1 convert whole number to a fraction
2 invert and multiply
(Is that a dash or a minus sign in front, of a minus your answer should me a minus)
Will sit down and get pencil and paper to do calculation. Let you know in a couple of minutes.

This is how I (very vaguely)
remember doing it.

hey, the board has actually been a wealth of knowledge. I lean toward experience rather than what I read.

I do have to laugh a little though...we are all experienced, mostly college educated and 4th grade math has us not 100% sure of our answers. lol And it is 7th grade math hahahaha

27 posts ... have you gotten a final answer yet, lol?

I started to try ...then saw the negative and threw in the towel.

 

[ScarletDave]

If it is truly:
-3 and 2/7 , divided by: 1 and 1/4, then the answer is:
-23/7 / 5/4 = -23/7 * 4/5 = -115/35 * 28/35 = -3220/1225 = -644/245

 

[ddsmugs]

Still waiting to use this math in my daily life

 

[hoquat63]

Still waiting to use this math in my daily life

Use it all the time to help my grand kids do their homework

 

[mikebal9]

I teach 6th grade math. Literally taught this today. Multiply by the reciprocal.

 

[Tango Two]

I teach 6th grade math. Literally taught this today. Multiply by the reciprocal.

So this is wrong?



Convert to decimal

-3 2/7 divided by 1 1/4 =

2/7 = .2857

1/4 = .25

-3.2857 / 1.25 = -2.6285

 

[Southern Gentleman]

I dunno. Hey, do you want a beer and some BBQ?

 

[red sail]

Tango. you didnt prove your answer with fractions, if I was a teacher I would probably mark you wrong. QED ha
I think the point of working out equations for kids, is to prove they understand the process and not pull out their calculators like you did.

 

[Tango Two]

Tango. you didnt prove your answer with fractions, if I was a teacher I would probably mark you wrong. QED ha
I think the point of working out equations for kids, is to prove they understand the process and not pull out their calculators like you did.

I’m just asking if I did it right and if that’s the right answer

 

[lne001]

I’m just asking if I did it right and if that’s the right answer

The correct answer, I think, is -2 154/245. Your answer of -2.6285 stops at the fourth decimal, while 154/245 actually equals 0.6285714285714286 etc. The correct answer must be a fraction to be precise.

Of course I've been wrong once on this already, so be warned.

 

[BigWill]

11/4 cannot equal 5/4

I think my math is correct but I may have screwed up the positive and negative

No problem here, but watch jumping your car....

 

[Extra Point_rivals157299]

That is simple division. She might be doing it on a calculator so she can't explain the steps.

 

[TheHandOfChaos]

OK, so, my Niece is staying with us for a while and taking pre algebra - She has a number of fraction equations to do and when she does them, it just isn't computing in my old mind and she can't walk through the steps and seems she is just giving answers she was giving- BTW- her teachers are doing that a lot. Giving quizzes and answers

-3 2/7 divided by 1 1/4 = 23/798

Is this actually the correct answer and how do you get to that answer?

-((3x7)+2)/7 * 4/5 (reciprocal of 5/4) =

-23/7 * 4/5 =

-92/35 =

-2 22/35