No, because I think that &quot;easily stored on a computer&quot; is too vague and reductive.<p>I apologize if I have been too unclear about my point. My point is that your position is unfair. Your position seems to be that rational arithmetic is an obvious choice that other languages have been too lazy or stupid to adopt as their default. My point is that rational arithmetic is a fine choice for many things, but it is not a strict improvement over other number representations. Yes it can handle 0.1 + 0.2 = 0.3, but your implied conclusion that it is an obvious &quot;default&quot; choice is not accurate. It is not as perfect, and floating point is not as bad, as you seem to think.<p>Yes, doubles have lots of values they can&#x27;t represent perfectly, but so do rationals. Like sqrt(2), sin(1), pi, or any calculations involving numbers like these.<p>Yes rationals can represent lots of numbers perfectly, but if you&#x27;re keeping everything exact these can start to take lots of memory. Some slides I found about Perl 6 indicate that Rat values lose precision if the denominator gets too big, to avoid using too much memory.  If this is true, the Rat type shouldn&#x27;t be thought of as an &quot;exact&quot; type any more than double -- it could cease to be exact even if you stay away from inherently non-rational number like I listed above.<p>What I&#x27;m disagreeing with overall is the dichotomy you are trying to create of: double=approximate, Perl 6 number=exact. Neither of those are really very true. There are cases where double is exact and cases where Perl 6 is not exact.