Stuck!

[Flosi]

Any suggestions?

Question.

48, 24, 72, 18, 90

Answer is 15

Does anybody know what the sequence is?

Flosi

[Kiwimum]

It looks to me as alternatively dividing and multiplying by increasing one number each time:

48 / 2 = 24
24 x 3 = 72
72 / 4 = 18
18 x 5 = 90
90 / 6 = 15

[UmSusu]

Hi Flosi

The sequence alternates between multiplication and division, whilst moving up one number each time:

48 /2=24
24 x3=72
72 /4=18
18 x5=90

So: 90 /6=15

It's quite refreshing for me to be answering rather than the one asking question!

Regards, UmSusu

[UmSusu]

Kiwimum beat me to it! I need to learn to type quicker

[Flosi]

Wow

Thanks guys for a quick response.

Wish I could think that quick!

Flosi

[menagerie]

What levels are these qus? Are they 11+ standard? They seem very challenging to me!

[patricia]

Yes they are 11 plus standard.

Patricia

[menagerie]

Thank you, Patricia.

Roughly how long would they be expected to spend on a question like this? That's quite a lot of mental maths trial and error to see which pattern emerges, isn't it?

[patricia]

With practice, and making notes, these questions should be completed within 30 seconds.

I weekly give daily exercises to include doubling/halving/multiplying/division/adding/subtraction a little every day, 10 sums at the breakfast table will give surprising results over a short period of time.

Divide an A4 sheet into 6 sections in each section place 10 sums, each section containing the same type of problem, all adding, all subtraction, all doubling/halving etc etc. Do not use huge numbers, once the smaller numbers have been mastered the larger numbers become easy.

One section a day is not too much on the work load.

Patricia

[menagerie]

Patricia, you are brilliant. Thank you so much. Your support is priceless.

When I set these daily sums, do you advise straight multiplying, for example, or a multiple +1, so they get into the habit of looking for the hidden extras?