Topic: URGENT MATHS HELP NEEDED!

[montysmum]

Find a two digit odd number that is a square number and the product of whose digits is 8

Can anyone give me the answer to this?  I am trying to help my 10yr old niece with her homework and this may as well be in Greek!!

[SMD]

81.

[Chakan]

81

[montysmum]

So how do you get that answer then?

Thanks a lot by the way

[Chakan]

So how do you get that answer then?

Thanks a lot by the way

Find a two digit odd number that is a square number and the product of whose digits is 8

2 digit odd number = 81
is a square number = 9x9 = 81
product of the 2 numbers = 8 ... 8x1 = 8

[exiledintheUSA]

81.

81

I think it's 81.

[Drippy Dick]

Say the number is "xy"
Then x.y=8
x.y=b.b (b is the number its the square of)

Fuck this. Trial and error is easy

[Chakan]

Say the number is "xy"
Then x.y=8
x.y=b.b (b is the number its the square of)

Fuck this. Trial and error is easy

Well to be fair there are only 4 number it could be. 81,42,24,18

[montysmum]

Thankyou so much!  I really appreciate your help.

She was getting so worried and upset that it didnt seem to make sense, and I was no help at all.  You really have saved the day.

Bloody Hell, I am dreading it when she starts to get more advanced maths homework, I am struggling now!

Thanks again

[exiledintheUSA]

Bloody Hell, I am dreading it when she starts to get more advanced maths homework, I am struggling now!

You just wait untill the 11 times table comes home.

[Brian Blessed]

It's 81.

["Nookie".]

Well to be fair there are only 4 number it could be. 81,42,24,18

And only one of those is odd.

[mbyx6cg2]

81 is the answer

["Nookie".]

81 is the answer

Are you sure?

[Brian Blessed]

And only one of those is odd.

Who are you to judge others?

[Zappa]

Are you sure?

Impressed that two stars I thought were thick got this

But just to be sure can we have a poll?

[SMD]

Find a two digit odd number that is a square number and the product of whose digits is 8

Can anyone give me the answer to this?  I am trying to help my 10yr old niece with her homework and this may as well be in Greek!!

If you want to teach your niece how to figure it out, tell her she should break down the question into parts, so:

1- two digit odd number
2- square number
3- product of digits is 8

The easiest point to start from is 2, you need to list all the square numbers so 1 is 1 squared, 4 is 2 squared, 9 is 3 squared, etc.  Then you cross off all the even numbers and single digit square numbers, for example:

1, 4, 9, 16, 25, 36, 49, 64, 81

So now you've covered 1 and 2. This just leaves you with the last one, which is now dead simple because you've written them down and even if she didn't twig on instantly that 8x1 = 8 when you do them one by one it'll be 2x5 = 10, 4x9 = 36, 8x1=8 and it's solved.

In short, it's easy when you break it down The trick is knowing how to.

[The Gulleysucker]

Several ways of doing it.
One is by Chakans method, provided you know your times tables and the ones that result in squares ie 2x2,3x3,4x4 etc. I'm not sure how much of that is taught anymore at primary schools. We had to memorise upto the 12 times tables when I was a kid and be able to answer any of them during mental tests each morning.

Another if you are unsure is a quick deduction process, ie

If the answer has to be a two digit number it must be between 10 and 99 and since they say it's an odd, its square root has got to be either 1,3,5,7 or 9.

Why? Well even numbers multiplied together always result in an even answer and we want an odd one, and any larger whole number than 9 squared would result in 3 digit answers ie 11x11=121.

And if the product result has to be 8, it must also be a answer less than 90 as otherwise the product would be greater than 8.

So, we are looking for an answer that is less than 90 and the nearest number from our potential candidate list from above to get that result is 9, and sure enough, 9x9=81, and the product of the digits in 81 is 8.

[Seebab]

81 I think???

[Elli]

Say the number is "xy"
Then x.y=8
x.y=b.b (b is the number its the square of)

Fuck this. Trial and error is easy

Least helpful post ever for someone struggling with their daughter's homework

[Brian Blessed]

Least helpful post ever for someone struggling with their daughter's homework

haha, yes. May as have said "employ Fermat's Last Theorem and Bob's your Uncle"

[montysmum]

Thanks again, she has gone home happy now

I wish I had paid attention at school all those years ago.  I am ok at English, but Maths was never my strong point.

Maybe it is time to start brushing up on my learning too

[Elli]

One other small point. Does she know what a square number is, and what "product" means?

If not, you need to raise it with the teacher. They shouldn't be setting homework the kids don't understand (unless it's to see where they are at the start of a topic, in which case I would always put a note on to reassure the parents, cos the parents of my class get WELL stressed about homework, even though I've told them a million times to bring it back on a Monday and ask, as it's not due till the Tues).

[Elzar]

83.

[rednich85]

Think it's 81

[Lady_brandybuck]

Dyscalculia is a bad thing... my thoughts aer with you montysmum...

[montysmum]

One other small point. Does she know what a square number is, and what "product" means?

If not, you need to raise it with the teacher. They shouldn't be setting homework the kids don't understand (unless it's to see where they are at the start of a topic, in which case I would always put a note on to reassure the parents, cos the parents of my class get WELL stressed about homework, even though I've told them a million times to bring it back on a Monday and ask, as it's not due till the Tues).

She did know that (she told me what it meant) I think it was just how it was worded that confused us both.

Every night I end up surrounded by screwed up bits of paper trying to work things out, and she just usually does it all in her head!

It brings back memories of all those sums I used to battle through in class - you know the ones that start "A train travels at 40mps, stops three times, has a cup of tea and a natter with Thomas, .............., what time does it arrive at its destination" sort of thing

[SMD]

One other small point. Does she know what a square number is, and what "product" means?

If not, you need to raise it with the teacher. They shouldn't be setting homework the kids don't understand (unless it's to see where they are at the start of a topic, in which case I would always put a note on to reassure the parents, cos the parents of my class get WELL stressed about homework, even though I've told them a million times to bring it back on a Monday and ask, as it's not due till the Tues).

Good point, my little sister had a lot of trouble with things like this.

[Buzz Killington]

81 I think, can anyone confirm it

[AllyouneedisRush]

Why is x^0 always equal to 1?

[SMD]

Why is x^0 always equal to 1?

Why not?

[redsox0411]

Why is x^0 always equal to 1?

Probably because x^0= X^1 divided with x^1 thus being 1

[SMD]

Probably because x^0= X^1 divided with x^1 thus being 1

Actually the best way to think of it is that the power is the dimension, so x² is in two dimensions, x³ is in three dimensions and so on. So if x¹ is in one dimension (i.e. a line) then x⁰ will be simply a dot. Hence it always being 1.

[blert596]

Strangely enough we were looking at antenna beamwidth angles and lengths (by propogation) on Wednesday and totally out of the blue I managed to remember the Cosine rule and the Sine rule. And managed to work out what I wanted from it.

Quite impressed with that seeing as its been more than 20 years.

Oh, and I used the trial and error method on the above ie. 16 nope, 25 nope, 36 nope, 49 nope, 64 nope, 81 bingo

[montysmum]

You are all way too clever!

Puts me to shame 

[Brian Blessed]

You are all way too clever!

Puts me to shame 

Look at it this way; about 20 people have responded to the topic, which means 29,980 RAWKites have swerved it as they had no idea(and yes, every single one took a look)

So you aren't doing bad!

[scouser4eva]

id say 81

[AllyouneedisRush]

Actually the best way to think of it is that the power is the dimension, so x² is in two dimensions, x³ is in three dimensions and so on. So if x¹ is in one dimension (i.e. a line) then x⁰ will be simply a dot. Hence it always being 1.

see what you did there, but it is based on the laws of indices.

[SMD]

see what you did there, but it is based on the laws of indices.

Erm, yes? But that's why it works the way it works.

[AriGold]

81 mate.