#1897 factor(-1/3)*3 doesn't simplify

[Stavros Macrakis]

factor(2/3)*3 => 2 OK
factor(x^2-1)/(x+1) => x-1 OK
factor(-1/3)*3 => -3/3 NOT OK should be -1

factor(4/3)*3 => 2^2 Arguably OK, arguably not
factor(4/9)*3 => 2^2/3 similar
I thought something helpful might be going on here so that part(factor(10!),3) would yield 5^2 rather than 25, but it doesn't!