Two 2s can be combined in many ways to express different numbers. Here are some!
2/2 = 1
2 + 2 = 2.2
(2^2)! = 24 (4! means 4x3x2x1) (2^2 is 2 to the power of 2)
Can you write an expression that has the value of exactly 5, using:
- Two, and only two, 2s, and
- Any mathematical symbols or operations?
Answer: This teaser was a test of both maths and keyboard skills:
Andrew Knox, Rubbond International, Ohé en Laak, The Netherlands;
The square root of (.2 to the power of minus 2), i.e. the square root of (1/.2) x (1/.2), or the square root of 1 divided by .04, or the square root of 25.
John Bowen, consultant, Bromsgrove, UK:
Sq Rt of [0.2 to the power of -2] =5 / ie Sq Rt [1/0.04]
Michele Girardi, Scame Mastaf Spa, Suisio, Italy;
5 = Sqroot( inverse.log(2) / inverse.sqroot(2)
Paul Knutson, textile engineer, Timken Belts, Springfield, Missouri, USA
Stephan Paischer, head of product management special products, Semperit AG Holding, Vienna, Austria;
Chrystelle Tandonnet and Indrayush De, application & technology development, KSB SAS Pompes. Gradignan, France:
And finally this extra one given by a “mathematician passing nearby” Michele Girardi’s desk: 5 = (2-i)*(2+i).
Well done to all above and everyone else who had a go.