How to calculate 0.3log(base 2)0.3 using fx-991ms calc

Your calculator knows only the decimal logarithms log or log_10 and the natural logarithms (ln or log in base e).
So you cannot compute directly the logarithms in any bases other than 10 and e.
A workaround consists in using the relation
log in base b of a number a (log_b (a))
log_b(a)= (log_10(a) ) / (log_10 (b))
or the relation
log_b(a)= ln(a)/ln(b)

log_2(0.3)=log(0.3)/log(2) where log is log in base 10
Similarly
log_2(0.3)=ln(0.3)/ln(2)
As to the multiplicative factor you had at the beginning of your expression, just multiply the value obtained by one on the formulas above (both formulas will give the same result) by 0.3

For fx 991ms users finding log 2 base 1024 press log1024 divided by log2.......

For fx-991ms users in finding 0.3 in base two you press log 0.3 divided by log 2(log 0.3/log ).