"Math" puzzler on whitehousekids.gov

Factual Questions
1

OK, this is strange. If you go to the following URL, you are presented with this grid, with one value missing. You’re supposed to fill in the missing value. Through trial and error, I’ve found the answer, but I certainly can’t figure out the pattern. None of my friends can either. For what it’s worth, I have a BS in computer science, and one of my friends has a degree in math.

http://www.whitehouse.gov/kids/math/elementary/chl_111.html

The grid consists of 4 2x2 blocks and looks like this:



8,2  3,3  2,4  12,?
9,1  4,4  3,6  3,2

You’re supposed to figure out what the blank is, represented by ? abov. If you’re interested, the answer is:

2

Can anyone explain what the pattern is? Are we overthinking this?

TD

2

I got as far as noticing that you can change the operator for each pair of number on the top row to equal six. I can’t figure out how that fits with the second row though. Maybe that helps (or maybe not).

3

This could have to do with the kid’s game 24. You have to use all four numbers in conjunction with operators to create the number 24.

For example:

8x2 = 16
16 + 9 = 25
25 - 1 = 24

how about:

3x4 + 3x4 = 24

so for the last box:

12x2= 24
3-2 = 1
24x1 = 24

4

Then again, 2 wouldn’t be the only correct number if what I was thinking was what they were going for.

5

Ahh, the irony.

6

You were probably overthinking it. It’ll be a head slapper once you see the answer :stuck_out_tongue: :

The elements of each 2x2 grid result in a product of 144 when multiplied. Thus 144 / (1232) = 2.

7

Yeah, 3 would be another correct answer.

12 * 3 = 36
36 * 2 = 72
(blank) 72 / 3 = 24

jrand’s answer is correct. I am humbled. :smack:

8

Now, that’s just gross. :smiley:

9

…and that’s why we choose not to do elementary school math puzzles.

10

The numbers are arranged in a pattern that implies row-by-row or column-by-column operations, but the answer has nothing to do with that. They could print the numbers in random colors or different typefaces, too, and send it to Mensa.

11

Stupid kids these days are too damn smart!

12

There a worse one:

http://www.whitehouse.gov/kids/math/open/chl_114.html

This is the “Open Challenge”

No idea what the answer is, or how to get to it. Good luck!

13

92 - do I win anything ?

14

So that I don’t pull out what little hair I have remaining, please tell me how you
came up with this answer?

Thanks.

15

The middle school one is also confusing

I think the answer is 10 cents but that is not the answer they want.

16

You didn’t read carefully. The bottle doesn’t cost a dollar, it costs a dollar **more ** than the soda.

So soda costs x. Bottle costs 1.00 +x. Total is 1.00 + 2x == 1.10.
x = 0.05

A nickel.

17

Example : 15 @ 24 = 123 15 @ (83) = 123 158+3=123

It seems a little haphazard to me, and I’m not sure what the word “binary” was doing in the original question (different maning than what I’m used to ?). Still it’s more fun than IQ tests !

18

I’m still missing something here. If the answer to the problem is 10*9+2=92, why couldn’t it also be 63, 36, 29, 181 or 28? How do you select which multipliers are used?

19

The binary just means that the operation is applied to two numbers. The + , -, /, X are all binary operations as well.

20

Agreed - as far as I can tell there’s no obvious rule - evens, odds, primes, lowest sum, highest sum… The only rule I can see is “the ones that give the desired solution”.