First, next Friday I am speaking at a special conference for A-level students on science and pseudoscience. If you are a teacher or a student or even a normal person, and interested in coming along, the details are here.

Second, here is the Friday puzzle! A simple one this week, can you make the following equation correct by moving just one number…..

62 – 63 = 1

As ever, please do NOT post your answer, but do say if you think you have solved it and how long it took. Solution on Monday!

68 comments

1. Rob says:

🙂

1. Chris Macdonald says:

Wow! I managed to get this really quickly. It’ll probably just serve to bring me down to earth harder next friday

2. Must be missing something obvious. I’ve tried with “number” and also with “numeral” and either way can’t make it work…

3. PeterM says:

Not sure I understand the question …

4. Benjamin Willard says:

Took me a few minutes; had to count on my fingers too.

5. Sourabh says:

I *think* I have the solution. Took a few minutes of staring at the equation.

6. AhavahRachel says:

Got it immediately, but I’m a computer scientist, so it seemed pretty obvious to me. 🙂

7. Tort says:

Got a solution straight away but it is very liberal with what you could call a number (when it comes to moving one number). Is that the correct solution?

1. I think I’ve done the same, but I can’t help feeling this is not the answer he’s after?

2. Jo says:

I reckon we’re on the same track, but I’ll be disappointed if that’s actually the answer! I suspect it’s not.

3. Tort says:

I was wrong. I was thinking if you move the top part of the equals sign it becomes 62 = 63 – 1 this is wrong. You can do it by moving one number which is after all what the puzzle asks for.

I hope this doesn’t break the answer rule but I can see I’m not the only one who found this incorrect solution, the right one just hit me then when I checked to see if anyone had corrected me.

8. I’m missing something….is the question correct?….. Is it really to “name” or is it to read “make” the equation correct by moving just one number? I’m clueless right now….have to retry later maybe after some sleep….it’s about 2 am my time and not gone to bed yet…..will try later today….

9. M says:

Nah, can’t make it work.

10. “The class are all beaming . . .” It are, are it?

Was the PDF drawn up by a teacher or a student? Obviously not by a NORMAL person!

1. Sorry, class can be singular or plural depending on the context. Just like staff, crew, group, etc.
‘The group is in the classroom. The group are all happy.’
‘The crew are revolting, sir.’

2. Rob, this usage is very rare in American English, so I’m guessing that’s what The Pick Man is familiar with. On this side of the pond, we almost uniformly treat group nouns as singular — “the team has taken the field”, “the media is in an uproar”, etc. The phrase above might best be re-worded in AmE as “The students are all beaming . . .”

3. Yes, I had heard that it was rare in American English. I guessed that might be the case – however, the Pick Man’s blog (which is very good, btw) implies that he is British, or at least living in Wales.
Sorry to be pedantic about his pedantry – pedants of the world, unite! You have nothing to lose but your apostrophes, collective nouns and mistranslations… he he he. 🙂

4. TYVM, Rob. I get very little feedback. It’s good to know that somebody actually reads it.

Yep, Cockney origin. Now homogenised British.

11. Charles Sullivan says:

What does “name” mean? I’m working on it.

12. Charles Sullivan says:

You mean “call” when you use the word “name”?

Just checking.

13. Nick Sharratt says:

Yep, got it in about 10 seconds. No freaky interpretation of ‘number’ needed.

14. Simon says:

Powerful puzzle this week, professor!

As well as by moving one digit, I can also solve it by moving one (non-digit) pen stroke. 🙂

15. Joao Pedro Afonso says:

This is a difficult one. The only solution I can think off, doesn’t comply with what is been asking 😦

(I hope it is not one of the famous late corrections after)

1. Joao Pedro Afonso says:

Okay, I got it… but only because of two comments that combined, are deadly to any puzzle solver. I’m not sure I’m happy. For one, I don’t have the time, for another, I probably would have said, “why didn’t I thought on that?”, surprised and amazed, Monday… this way, I feel I cheated. Definitely, I should stop from reading comments before solving the puzzles. 😦

16. Craig Forrrester says:

Once I learned to stop thinking so orthogonally, the answer presented itself.

17. Berber Anna says:

I can do it by moving just one number, but I’d need to fiddle with the non-number parts a bit, and I’m afraid that would constitute cheating.

18. Martha says:

I’ve seen this one before and I don’t think it’s easy at all. It’s not the kind of thing they’d allow on Countdown!

19. Martin says:

I was weakening, until I found the power to solve the puzzle.

20. mittfh says:

Depends on whether you can add a sign or not…

21. Timdifano says:

If this is a matchstick puzzle it is easily done, I have another answer, but not a s good.

22. Sneaky. Got it after about 15 minutes and much scribbling on scraps of paper.

23. c00 says:

I have several answers for this puzzle, none of which seem so obvious that they would be the answer Richard is looking for and some responders are so certain about, it being the right one.

But given the loose bounds of the text, I have at least 3 solutions which are in certain interpretations correct…

I shall be smug about it on monday.

24. Craig says:

Got a few different answers. Not sure which one is the correct interpretation of the question.

25. Idiot mathmo says:

Got it in about a minute, once I’d exhausted the obvious options and started thinking laterally.

26. By far, the easiest puzzle ever posted here. Even a normal person like me could find the answer right away.

27. Mike says:

I’m not patient enough… Got it after putting a couple comments together.

28. Got the non-number one first and then has to think for a minute to get the right answer.

29. Marion says:

I’ve got an answer but I’m not sure if it’s right. I’ll have to wait until Monday to find out!

30. me says:

one comment definitely gave it away for me

31. Took me a little while to get it but not too long. Everyone was mentioning not thinking laterally so I was trying to flip # but that didn’t work and then it hit me.

32. Victor says:

There are actually 2 answers, both wich are correct given the way the question is posed.

Now bite my nails till Monday to see wich one your after.

33. Alex says:

finally got it after about 10 hours

34. Steve says:

Hmm…I got stuck on the wording, I think saying to move one number is misleading…since their are only 3 numbers, but 5 digits to work with and it can’t be done using the 3 numbers you’ve been given.

1. Martha says:

Yep, by ‘numbers’, he means ‘digits’. I _think_ that’s the only bit of ambiguity in this one

35. if you are not sure if it’s correct then you don’t have the correct answer. once you get the correct answer then you won’t question the correctness of it xD

1. Mystery says:

good one, but rather the solution than a clue

36. mikekoz68 says:

Got it in less than 10 seconds! A first for me

37. Got it- and I’m bad at math!

Then again, you don’t need to be a math whiz to figure this out.

38. slightly_skeptical says:

10 minutes finally got it. Good one.

39. Sally says:

Got it. Took a few minutes at least.

40. Matt says:

Good one. Took me, on and off, bout 20mins.
So glad I didn’t scroll beyond first few comments before solving: some of you guys just can’t help yourselves can you?
Comments on here help thickies like me know that the puzzle can be solved and maybe iron out some ambiguity: It is very frustrating to read a BIG clue when all your seeking is assurance.
Idea: Have a ‘suppress spoilers/clues’ button on comments
or,
open up Monday’s answer + comments page on Friday with Richard updating it on Monday with his answer. Then all the smart arses can post there instead.

OMG I really need to get a life lol.

41. Ken Haley says:

Finally got it after about 15-20 minutes. I don’t believe you guys that say you got it in less than 10 seconds.

42. Read it and tried for a bit yesterday, slept on it, still can’t figure it out.
I’ve read all the comments, even watched that boring cartoon thing, still nothing.
I feel dumb as a door

I’ve run through all permutations of digit replacements, no equation turns out true.

I had the match-stick solution after a minute on friday, but the digit solution is just long gone for me.

I’m frustrated 😦

43. Zikero says:

“If you are a teacher or a student or even a normal person”
Teacher and students are abnormal people ??

44. TS says:

Got it!, I used the Force…

45. Jerry says:

Just remember that you can not apply the rules for working with equations to this problem because it is not an equation.

46. erica says:

Took several minutes of fairly mechanically trundling through the possible variations. In retrospect, should have leapt out at me….On another day, it may have done.

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