# Math opportunity.

coolgunguy
Senior MemberPosts:

**6,610**Senior Member
As a 'make work' sort of assignment, the boy child brings home a twenty question brain teaser. The rules are as follows: Using only the digits 4, 7, 9 & 9, and using any operations necessary, come up with the numbers 1-20. He did pretty good on his own, and I helped with a few...but we can't seem to come up with any way to make 19.

Any ideas?

The teacher did say that some of the problems may be unsolvable, but after working through the others, I feel like this answer is right there in plain sight just waiting for us to realize we were looking at it the whole time.

No, I'm not doing his work for him, but I don't mind helping him either. This was more or less "Do what you can"....

Any ideas?

The teacher did say that some of the problems may be unsolvable, but after working through the others, I feel like this answer is right there in plain sight just waiting for us to realize we were looking at it the whole time.

No, I'm not doing his work for him, but I don't mind helping him either. This was more or less "Do what you can"....

"Bipartisan" usually means that a bigger than normal deception is happening.

George Carlin

George Carlin

## Replies

24,713Senior Member8,258Senior MemberWWJMBD?"Nothing is safe from stupid." - Zee

7,939Senior MemberGun control laws make about as much sense as taking ex-lax to cure a cough.

6,610Senior MemberSorry, no joy, have to use 4 once, 7 once, and 9 twice. Like I said, it may not be possible, but my gut tells me it is. He worked out fifteen of the numbers on his own, got another four with guidance, but I'm afraid I've helped as much as I can without getting help of my own.

We've used both the square roots of nine and four, we've used exponents...for example: (9/9) to the 47th power = 1. The numbers can be used in any fashion, but only those four numbers can be used. Another example...(I'm not sure how to get square root brackets on the confuser, but you'll get what I'm doing) Square root of 4 (2) times the square root of 9 (3) times the square root of 9 (3) minus 7 = 11.

George Carlin

6,610Senior MemberWell, I said I felt like the answer was staring me in the face all along...:bang:

Thank you Chris!

George Carlin