This small package (usable with Plain e-TeX, LaTeX, or others) with no dependencies provides two fast expandable macros computing logarithms in base 10 and fractional powers of 10. They handle arguments of 9 digit tokens which stand for either 1 <= d.dddddddd < 10 (for the log) or 0.xxxxxxxxx (for powers of 10). They achieve a precision of 1ulp for the logarithm and 2ulp for fractional powers of ten. Extension to other numerical ranges has to be done by user, via own macros or some math engine. The xintexpr package (at 1.3f) imports the poormanlog macros as core constituents of its log10(), pow10(), log(), exp() and pow() functions.