GCHQ Christmas Card Puzzle

[noblegiraffe]

If anyone fancies having a go at the GCHQ Christmas card puzzle it's here https://www.gchq.gov.uk/files/2023%20GCHQ%20Christmas%20Challenge.pdf

I was staring at the stupid gift tag one for hours! Google helped there.

I've completed the puzzle but while I know the answer to Q5 part 2 I don't know why it's the answer so if anyone has any subtle hints they would be gratefully received.

I have completed puzzles 1,2 and 4 so far fairly easily. Will keep going and see if I can do the rest but it might take a while for this old brain to work them out!

Thank you this is really good!

I've got the final answer, and worked out 1,2,4, 5 (except for 5b) and 7.

I know the answer to 6 but I don't know why it's the answer.

No idea what 3 is, but I think I have one group - not that it's helping at all!

Eta, I think I may possibly know what the 1 and 0 means, but if I'm right it's not helping me as I've never understood the thing that I think the 1 and 0 is referring to!

I really enjoyed this! I worked out 1, 2, 4 and 7, then was able to figure out enough of the final answer to then work backwards and solve 3 and most of 5 (can't get 5c though) and deduce the answer to 6, though I still don't know how to solve it.

My facepalm moment was not realising how to connect the answers to the final answer. I worked it out through a process of deduction (how many letters in each answer) and then realised I was a plonker and had given myself a lot more work 🤦

I realised that once I had those three I could work out the final challenge and then have worked back to find the answers to the rest of them. The whole thing has taken about an hour. I'm happy with that, just sorry my late DH wasn't around for a more competitive challenge as he would have loved it too.

The gift tag is the only one I got right away

You got the gift tag right away?

I set this for my y11s as a fun lesson on Wednesday.

I raced them to see who could finish it first. They worked in pairs and I worked alone. I won! They did really well though and several finished it in the hour.

When you write a number in binary, the columns are worth 1, 2, 4, 8, 16, etc (each doubles in value) from right to left. A 1 in the column means you add that value to the total, so 10110 means

16 value column = 1, so add 16
8 value column =0, so add 0
4 value column = 1, so add 4
2 value column = 1, so add 2
1 value column = 0, so add 0

Total is 16+4+2=22

For anyone that has enjoyed this, there is a GCHQ puzzle book available to buy that you might also enjoy.

We've just finished this.
I've been carefully avoiding this thread until it was done, but bookmarked it in case we needed help. Amazingly we didn't but did take both me and DH to get there in the end.
I do love a bit of problem solving at Christmas!

Someone please help me with 7 its driving me potty!

Have a look at the second line - does it remind you of anything else you've read?

@BubbleBee123 read the clue to seven again, very carefully.

plus that gq'l on the bottom line has to be it's

Thanks for this. Between three of us we got 1 - 5. Then worked out the final challenge from there. So we have the answers to 6 and 7 but no idea how to get them from the questions themselves 🤷🏻‍♀️ But great fun.

When you have solved it all here's an Easter Egg to put the answer in context.

Well I’ve kept this one side to do today. I’ve worked out everything except 6 and I’ve got the code for 7 but I can’t find the word!

The word is right there! Staring you in the face!

All I can think is GCHQ but that doesn’t change to anything using the code.

Have you decoded the message in the same layout as it is written on the card? The word is not in code, it can be read straight from the message.

Thank you @noblegiraffe , enjoyed that.
Reassured to know my brain hasn't completely given up after 2 days of doing not much besides eat, drink, cook and wash up!

I want to know if @TeenDividedhas looked at this!

Done it!

The only bit I couldn’t get was the second and third ones of number 5, even now I know the answer I can’t work it out.
I sent it to my mother and I’m rather pleased that I found it easier than her, she is very good at stuff like this.