Maths help please!

[DeceitfulMummy]

Looking through DS's homework. The top one is correct - according to him he did it in class with the teacher. I don't see why it's correct but also can't figure out what it should be. And the others? What obvious thing am I missing? It's a long time since I did maths!

@noblegiraffe ok then explain it to us differently then

But it's not about explaining it to you, the OP wants to explain it to her Y7 child who is very weak at maths.

She should simply write that he cannot do the homework.

For the third example, I compared the answers for 5 and 40. I started by saying by saying 5*8 = 40.
5 => 1.5
40 => 12

1.5*8 = 12, which means that the function (3n/10) must be a fraction without any addition or subtraction. Then I worked out the fraction. I definitely didn't just see it.

@noblegiraffe I'd like to know how you should explain this - at least I've avoided calculus 🙂

Argh, should have previewed - that meant to say:

For the third example, I compared the answers for 5 and 40. I started by saying by saying 5x8 = 40.
5 => 1.5
40 => 12

1.5x8 = 12, which means that the function (3n/10) must be a fraction without any addition or subtraction. Then I worked out the fraction. I definitely didn't just see it.

Well then don't denigrate someone else's explanation if you're not prepared to give your own version

There isn't an explanation that's appropriate for the OP's DS that I can think of. It's a shit task.

For 1) I would spot that it's double the original number plus 1

For 2) I would spot that the two numbers multiply to make 120 (they are inversely proportional but this won't be covered till Y10ish)

For 3) I would spot that e.g. the answer for 50 is 10 times the answer for 5, the answer for 40 is 8 times the answer for 5 and multiples of the provided answers to get the missing answers.

None of these are a coherent method that can be applied from question to question.

What maths set is he in OP? Could the set he's in be too advanced for him?
I remember doing nth term st school but not to that level, so I assume this must be top set maths.

This isn't an nth term task!

I agree wholeheartedly with noblegiraffe. I can’t think of a standard method which would be appropriate for a y7 who has difficulty with Maths.

I used to teach this method to y9s, although that would lead on to sequences with n squared in (quadratic sequences) for the students who found it easy. But y7s in their first term will have developed a lot in their Maths understanding by the time they are y9s.

Not in y7, but eventually?

I used to teach maths. This is not appropriate for year 7!

Not as written - nth term tasks don't normally give randomish terms of the sequence (except A-level I suppose). The second question gives terms 1, 3, 4, 5 which would be very confusing!

They are very easy.

1. 2n + 1
2. 120/n
3. n * 0.3

I've verfied the answer with excel.

I just spot the pattern. I'd say this is primary maths, but on for an advanced student. The maths required is just multiples of 2 and 3 but you need to be quite logical to solve it.

The first one I would expect my 11+ students to be able to work out, although it would be one of the harder ones.

I really struggled to work out the other 2. but would have got there eventually.

On that basis they should be able to do the first one in year 6. But not the others.

You’re right.

I wonder if @DeceitfulMummy ‘s DS can remember enough of how he did it with a teacher to give us a clue.

If it’s just - look at the numbers and see if you can spot a pattern - then it’s very hard if you haven’t been given strategies to try.

Once you have the pattern it could be much more straightforward to say whether or not they are proportional, but that depends on what definition of “proportional” the class has been given.

For method, I would say you try to spot if there common multipliers. For example, the first one is one off multiplying the first row by 2. The second one I spotted that 3 x 4 = 4 x 3 = 6 x 2 = 12. What it means is they all multiply to 120. The last one I spotted that it's a multiplication by 3. Like 5 x 3 = 15, 15 3 = 45, 50 3 = 150.

Hopefully, if your son is strong with his multiplcations, he can spot these patterns.

Bottom set.
Has no clue how they did it in class.
Only worksheet home, no books.
Is not strong on multiplications or anything to do with maths. Generally guesses his tables unless it's one he really knows, although he does know most of them now. But he wouldn't see that e.g. 5 is related to 1.5 even though he knows 3 x 5 =15. Has just told me half of one thousand is 5000.

It's definitely an inappropriate task. The teacher probably realized this and that's why they did an example together. But that example can't be used to work out the others.

It really needs to be a case of "DS tried but couldn't do this and I wasn't able to help him as I didn't want to confuse him further." If he's worried about getting in trouble, he could write in some answers so that it is "done."

So you do something with the top number to get the bottom number, and for each row the "something" is the same.

What he could do is graph the pairs of numbers. The first and third sets of numbers give a straight line.

But the second is a curve, where the smaller the top value is, the larger the bottom value.

So the "something" for the first and third questions is going to be a similar pattern.

But you know the second one will be a bit different.

So with the first and third, you have a look at the pattern.

"You do something to 2, and that makes it 5. You do THE SAME THING to 10 and that makes 21, You do THE EXACT SAME THING to 50 and you get 101... what is the thing you're doing?"

"Well 101 is 50x2, plus 1... Could it be that?"

Then you try it out...
2x2, +1 is 5 ✔️
10x2, +1 is 21✔️
60x2, +1 is 121 ✔️
Ok then, "something" can be "double it and then add 1".

BUT
You can do it either way around. You can try "what do I have to do to the BOTTOM numbers to get the TOP numbers?"

And you can also take pairs and conside them "sideways". For example, in the third set, how do 5 and 50 relate? Well, 50 is ten times 5. Now look at their pairs on the bottom row. How do 1.5 and 15 relate? Again, 15 is ten times 1.5.
So, you think, could it be that it's a very straightforward "if the top goes up because you multiplied by (a number), then the bottom goes up by multiplying by (that same number)?"
Check the other pair, yes, that works.

The middle one - I am guessing the topic may have covered how things can be inversely proportional . If one goes up, the other goes down, in an "if A doubles, B is halved. If A is quartered, B is multiplied by 4" and so on.

Consider area - if you have a rectangle 16 square metres.
If the length goes up, the width goes down, but length X width is always 16
1 X 16
1.6 X 10
2 X 8
4 X 4
8 X 2
10 X 1.6
16 X 1

If you plot those numbers you get a very similar curve to that from #2. So you know you're looking for some sort of
number1 X number2 = AConstantValue
pattern.

@DeceitfulMummy This isn't appropriate for bottom set maths. I think it is for year 6 or year 7 but only the top set. It's not strictly in the cirriculum I'd imagine, but more a 'fun' question.

For example, DC1 is in Year 8 and they are given parallel maths. But the teacher has said it's only for children who wants to stretch themselves. This feels like the same kind of maths questions.

Well I've just fought through a round of 1000g costs £22.5 how much is
100g
20g
40g
160g

He knows 2x2 =4 and 4x4=16 but for him 20/40/160 are another breed of numbers! No idea how they are related to each other.

Is this another from his work sheet? Can he see that 100 is 1/10 of 1000. And then 20 is 1/5 of 100. Then 40 is double 20, and lastly 160 is 4 times 40? It's a sequence of working out the answer of each.

Does it help him if he sees it - packs of sweets on a table and money to pay for them? Does he do any baking ? Numbers are marks on a page or a screen, some people find it easier to deal with physical things there in front of them.