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Make 284 using 4, 6, 7, 17, 24 once each and - and x

Posted: Mon Jan 21, 2008 9:00 pm
by cam
Make 284 using 4, 6, 7, 17, 24 once each and - and x.
Help.
We tried starting with 284 looking for factors, and adding each number on and then looking for factors. We would really appreciate some help and a method to give us some direction.

Posted: Tue Jan 22, 2008 9:43 am
by abcdef
Hi cam,
I also tried using the prime factors of 284 ( being 2 x 2 x 71) - which didn't help at all.
I ended up just trying a number of different possibilities - and ended up with:
((17-6) x 7 x 4)-24 = 284.

I.e 17 - 6 = 11
11 x 7 x 4 = 308
308-24 = 284.

Hope this helps
abcdef

Posted: Wed Jan 23, 2008 11:02 am
by cam
Thank you, we just couldn't see it.

Posted: Wed Jan 23, 2008 2:22 pm
by yoyo123
I play a game on this principle with my pupils.

Using a pack of cards turn up 2 cards to make a 2 digit number (or 3 digits if first card is a picture card.)

Lay out 5 more cards underneath and then try to make the target number using those 5 numbers once only .

Sometimes works, sometimes doesn't but it does get you thinking about and using number bonds and times tables. Good to compare how you both got to the number too.

You can play it as a contest 3 points for spot on, 2 points if +or - 1 , 1 point if within 5 of target