Make the number 21 using the numbers:

1, 5, 6, 7

 

you can use:

addition, subtraction, multipliaction and division

 

I promise you it is straight forward maths and NO tricks... you can only use each number once and you cant use say 15 (the 1 and the 5 together) and you cant do like 5^6 or anything.

according to my calculations it is NOT Possible.

 

unless you allow the addition of 1 and 0 in a ten or a 2 an 0 in a twenty to make a 1 or a 2 for example.

 

other than that, I don`t think it`s possible.

6/(1-(5/7))

wow!

 

it beats my: 7x1= 7

5x6 = 30

 

3+0 =3

 

3x7 =21 anyday )

lol, i do what I can

have you heard it before or had any help with it?

 

it took me a while to guess, i knew it must be divide by a number smaller than 1 but my calculator i was using was giving me stupid decimals which got confusing!

anyone in the UK and belongs to Mensa?

 

if my dad remembers he said he'd send it into the magazine.

Actually I knew that (after trying all my multiplications) if I was dividing something by 6, it would have to be less than one, so I tried subtracting one what I knew to be a decimal, giving me something like .2857~ect...

I checked it over, and it worked

Lucky guess really

hmm...

(5*6) - (7*1) = 21

 

lols

That equals 23?