Question type 18: Related Numbers

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boltew
Posts: 48
Joined: Thu Mar 20, 2008 2:38 pm

Question type 18: Related Numbers

Post by boltew »

My DD finds the 'Related Numbers' question types very difficult.

Example:
(7 [15] 8) (9 [14] 5) (6 [ ? ] 5)

Unless it's very obvious, she never manages to complete these questions. She struggles for ages and then gives up.

I must admit, they are not my favourite questions!

Does anyone have any hints/ tips on how to solve these questions quickly?
Snowdrops
Posts: 4667
Joined: Wed Nov 21, 2007 5:20 pm

Post by Snowdrops »

I didn't like them very much at first either.

Practise, practise, practise - the more you do them, the more you know what to look for.

You become very familiar with them and I did find over time that you 'see' them very quickly.
Image
2010 mum
Posts: 45
Joined: Wed Mar 11, 2009 5:21 pm
Location: London

Post by 2010 mum »

hello Boltew,

I hope this helps you.

Example:
(7 [15] 8) (9 [14] 5) (6 [ ? ] 5)


Answer:
By adding the numbers on both end you get the answer to the number in the middle.

So: 7 + 8 = [15]
9 + 5 = [14]
6 + 5 = [11]

I found it confusing initially, but my DD told me how to work it out.

I sometimes find that by working through the exercises together and saying out aloud helps. Don't ask me how, but it does for me and my DD

It also helps to get the "how to" or "parental guides" for any of the subjects you embark on.

Good luck
Thanks... 2010mum
sycamore
Posts: 686
Joined: Mon Oct 06, 2008 2:41 pm
Location: South Wilts

Post by sycamore »

Hi boltew, I've sent you a pm. :)
Y
Posts: 463
Joined: Mon Mar 12, 2007 12:49 pm

Post by Y »

Basically many of the questions involve two operations. So always try

Operation 1 = + ,- ,X, or, / (divide) the outside nos ; then
operation 2 = +, -, X or / by an integer, or by either the left or right outside number

So if you are stumped always try each of the 4 possibles in operation 1, then ask yourself which operation 2 would you need to do to get to the middle number. Does it work for both examples. If yes you've got it.
This is the simplest explanation I've seen of how to do these questions. (From an old post by 'guest' Hilda)
patricia
Posts: 2803
Joined: Mon Jan 30, 2006 5:07 pm

Post by patricia »

Dear Boltew

At the start of my tuition, I always write 'helpful' notes next to each type within the test that is left for homework. For type K bracket maths, I write the following:

Middle number has been made using the numbers either side.
Same rule must apply for all 3 sets.
Sometimes 1 operation. Sometimes 2.
Second operation can be:

1] + - x / [divide sign!] the same number.
2] doubling/halving
3] + - x / [divide sign] the number on the left or right of the middle number.


Whilst teaching, I always say:

If the number in the middle is bigger than the 2 either side then your 1st operation is probably adding or multiplying.

If the number in the middle is smaller that at least one of the numbers either side, then your 1st operation is probably subtracting or dividing.

I always emphasise the word probably, because there are times when this rule will not work, they are not to panic, if it doesn't work, thats fine, just try the other 2 operaions.

Patricia
polly0494
Posts: 91
Joined: Fri Aug 22, 2008 12:08 pm

Verbal Reasoning Type 18 Related Numbers - help!

Post by polly0494 »

Hi

I too struggle with these unless the answer is obvious (my daughter is usually able to work these out? but this one has us stumped!

(36 [8] 9), (50 [10] 10), (64 [?] 8)

the options are 15, 16, 17, 18, 19

I think the answer is 16 but I cannot explain why!

The other one is:
(15 [16] 17) (22 [25] 28) (25 [?] 31)

Again, I think the answer is 28 but I am not totally sure as the first series is increasing by 1, the second by 3 and the third by 3 - does that have any bearing or is it just the mathematical operation that is key here?

Can anybody help?

Many thanks

Polly
Guest55
Posts: 16254
Joined: Mon Feb 12, 2007 2:21 pm

Post by Guest55 »

(36 [8] 9), (50 [10] 10), (64 [?] 8 )

36 divided by 9 is 4 then double

this works for 50 divided by 10 then double

So missing one is 64 divided by 8 then double i.e. 16

.............................................................................

(15 [16] 17) (22 [25] 28 ) (25 [?] 31)

The middle number is the mean so (25 + 31) divided by 2 = 28
polly0494
Posts: 91
Joined: Fri Aug 22, 2008 12:08 pm

Post by polly0494 »

Thanks for your very quick explanation; why is it always so easy when you know the answer?? :oops:
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