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## Wedding maths?!

So, yesterday was my cousins wedding day, superb service and a great do. Not the sort of day where you expect to find maths lesson ideas, however, between the main course and dessert I was beckoned over to another table by another cousin. A young guest (13 year old) had foxed the entire table, and many others, with this little puzzle which he had plotted on a napkin:

I’d seen many like this before, but never this one. The task is to fill the middle boxes with numbers between one and nine with no repeats so that all the equations hold true. The young puzzlemaster was impressed that I solved it, as were his audience, but we left the rest of them trying for a while before he let them know the solution.

Needless to say, that’s starters sorted out for each classes first lesson back after Christmas! I like it when I can run starters across all classes like this, i like to ponder who will be quickest to solve. Last year I ran this which came from my favourite maths teaching blog, and was pleasantly surprised to find the winner was from year 7! (he even beat all the staff!) it was made particularly fun by the fact his brother, who is on course for an A in year 13, took 3 times as long to solve it!

1. December 23, 2012 at 1:45 pm

Thanks for linking to my blog -that’s one of my favourite puzzles.

In the one you’ve posted, there seems to be 12 boxes for 9 digits? I don’t quite get it. Sorry if I’m being thick!

Dave

• December 23, 2012 at 1:54 pm

Hi Dave,

The “link the blocks” puzzle is one if my favourites too. I’ve used it a lot since I discovered it.

The puzzle posted above, you only need to fill in the middle four, then the vertical equals signs take those numbers to the top and bottom rows to make up the equations. Sorry, I should probably have been clearer in the original post!

2. December 23, 2012 at 2:55 pm

Cool. That makes sense!

3. December 31, 2012 at 8:01 pm

I think I’m still being a little thick. I presume you don’t need to use all the numbers from 1-9.

Thanks
Dave

• December 31, 2012 at 11:52 pm

No, you need 4 unique numbers between 1 and 9 for the middle boxes, then the vertical equals signs take them up and down to the top and bottom rows, you must arrange it so the equations on the top and bottom rows hold true. Hope this helps, I think I was a little unclear in the original post.

4. November 6, 2014 at 4:52 pm

Could you possibly post what the second puzzle is as the link doesn’t seem to work? Thank you, absolutely loving the napkin one!

5. December 20, 2015 at 9:49 am

I feel so dim… If the vertical equals signs take the values up and down to the top and bottom rows then the top and bottom rows are the same? So what is the point of having them both? And in fact why even have the middle row? Not understanding this at all!

• December 20, 2015 at 9:55 am

The numbers in the top and bottom are the same, but operations are in a different order. The problem would work equally well without the middle row though.

1. January 7, 2013 at 5:12 pm
2. May 14, 2013 at 5:25 pm