Has anyone encountered or used the pental (base 5) number system? I came across it by chance when I was playing around with my grandson's Sharp EL-531W scientific algebraic calculator, which we had just bought for him at the supermarket for $12.99, so it's pretty much a low end calculator similar to the HP SmartCalc 300s. I am familiar with binary, octal and hexadecimal numbers for use in programming and computer applications, but I have never before seen the use of pental numbers (e. g. 6 decimal = 11 pental). So, at the risk of appearing grossly ignorant, what would be the application for such a number system? I've never seen it on any of my HP calcs; even the mighty HP-50g lacks it.

Please help me before I lose face with my grandson, who thinks I am the eternal fountain of knowledge.

Michael