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.

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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 :-)

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

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

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

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

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

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

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

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

This was my answer!

Congratulations to all the base-3ers!

I agree. The Base 3 stuff is inspired.

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

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

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.

That was a good one-it beat me!

10 squared is 100. 101-100=1

I didn’t get this one. Very good.

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.

Eh?

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.

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

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

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