After making her sit there for EVER playing this game to work it all through, my daughter was stuck and stuck and stuck with the remainder of 27. We'd done some arguing about it, with me suggesting different strategies from the kitchen where I was making dinner. I came in to finally help, and to my dismay, I found that I'd kept her at it for nearly 45 minutes when no answer exists!

We're trying to find 27 as a remainder with the cards as given:

18, 20, 21, 24, 27, 30, 32, 35, 40, 49, 50, 56, 60, 64.

Coming at it backwards...

64-27=37. Nope
60-27=33. Nope
56-27=29. Nope
50-27=23. Nope
49-27=22. Nope
40-27=13. Nope...and of course, they all get lower, and 18 is our smallest card to work with.

My daughter finally said in frustration: "27. 27 all by itself, or minus zero, is 27."

But that's not fair. All the others worked, but she hunted for a really long time for a remainder she couldn't come up with.

It was really disappointing and frustrating for her.

I should have mentioned we tried it from both ends, of course.

18+27=45 No 45 card
20+27=47 No 47 card
21+27=28 No 48 card
24+27=51 No 51 card
27+27=54 No 54 card
30+27=57 No 57 card
32+27=59 No 59 card
35+27+62 No 62 card
40+27=67 No cards higher than 64...

I'm on midnights and I'm usually easy to confuse when I'm working midnights, but I think I'm right about this one. If I'm missing something, I'm sorry, but I don't think this game completely works. My daughter's pretty sure, and called it "the most un-fun game in the universe." But that was a good while before we realised there was a problem with 27...she just didn't like the WORK involved (I absolutely loved it until we hit the 27 issue - it's a great exercise).

Dear storybookmum,
You are right, we just discovered that mistake at our annual meeting and we will revise it in the next version. I am so proud of your daughter for solving it as 27-0=27! That is thinking mathematically! Bravoo! This is the kind of mathematical thinking we are looking for in RS. I am sure we will have a job for her sometime in the future
Nancy

About that job opportunity....she's getting by in math now, without too many tears or fights, but she was still horrified to read your response. I'm afraid she doesn't plan just yet to submit a resume...maybe the years ahead will change her mind!