On Friday I posted this puzzle….

Can you move one numeral and make the following equation correct?

If you have not tried to solve it, have a go now.  For everyone else, the answer is after the break.

Move the ‘2’ vertically…..

Did you solve it?

I have produced an ebook containing 101 of the previous Friday Puzzles! It is called PUZZLED and is available for the Kindle (UKhere and USA here) and on the iBookstore (UK here in the USA here). You can try 101 of the puzzles for free here.

1. Very good. I thought you’d made a boo-boo in the wording and so I ‘solved’ it by moving one line of the equals sign to the left. So I was wrong but in a happy way 🙂

1. Anonymous says:

You didn’t solve it! The question was: Can you move one NUMERAL and make the following equation correct?

2. That’s what I just said! I was wrong. Read the message again.

2. Miko says:

Move the 2 to the other side: 101 – 10 = 21 (interpreted as an equation in base-3).

1. Good one with the base change. As a programmer I’m embarrassed I didn’t think of that.

3. littlechap22 says:

@miko : amazing! Thanks but how did you think of it?

4. isogulaleb says:

What about 101=102-1… though it is not the numeral moving but one line from the equation sign… 🙂

5. Antoine says:

In base 3 you could also do 110-102=1 !

6. Anonymous says:

You could also do 110-102=1 (base-3)

1. Artisticanne says:

7. Eddie says:

Congratulations to all the base-3ers!

8. -M- says:

Am I the first one who says “I got the original answer”?

9. Edd says:

Took a minute or so. I figured the puzzle would’ve been represented by matches, if the puzzle were about the +/-/= signs.

1. ctj says:

the fact that richard specifically used arabic numbers here clued me that this puzzle had something to do with moving the digits around.

it helped that i have a kid who is very into powers right now.

10. Indy says:

That was a good one-it beat me!

11. Sudhindra says:

10 squared is 100. 101-100=1

12. Julia says:

I didn’t get this one. Very good.

13. Anonymous says:

I got the original one, but like the base 3 version better. It’s also very cool that 21 has the same value in decimal as well as base 3.

1. lamanga2004 says:

Eh?

2. Eddie says:

Let’s see…
21 in base 3 = 7 in base 10.
21.0 in base 10 = 210 in base 3.
BTW did you know you can have fractional base number systems.
And yes, Dave, I’m probably a real blast at parties.

14. The Moron says:

The base 3 thing is ok, but I prefer the pictures of Richard Dawkins.

15. Henry says:

So damn easy. I solved it in less than a second.

16. I think you meant “digit” rather than “numeral” in the original problem.