Proctele apps in the App Store

Proctele apps in the App Store
Click the picture to see Proctele apps in Apple's App Store

Monday, February 14, 2011

NumberWiz example with solution-reasoning

How do you add, subtract, multiply and divide 3, 5, 7, 8, 25, 75 to get 127?


This time I'm showing how I reason to find a solution. 


First I thought that 127 is close enough to 125, so 5 x 25 = 125, need to add 2. Getting 2 out of 3, 7, 8, 75 was simple: 2 = 7 + 3 - 8. Hence 127 = 5 x 25 + 7 + 3 - 8.


Another thing I would try is adding 75 and 25 to get 100. Then it's a matter of getting 27 out of 3, 5, 7, 8. That's not so difficult. 27 = 5 x 7 - 8. Hence 127 = 75 + 25 + 5 x 7 - 8 = 100 + 35 - 8.


The NumberWiz game gave this solution: 127 = 5 x 3 x 8 + 7 = 15 x 8 + 7. Elegant.


What a great game this NumberWiz game! Visit http://proctele.se

No comments:

Post a Comment