A decimal fraction such as #ABCD.PQRST....# can be written as
#Axx1000+Bxx100+Cxx10+D+P/10+Q/100+R/1000+S/10000+T/100000+....# in fraction or simply
#ABCD+P/10+Q/100+R/1000+S/10000+T/100000+.............#
As we have two digits in #-0.33# (we are ignoring minus sign as it can be put later before equivalent fraction or percent immediately to the left of decimal point), it can be written as
#3/10+3/100=(3xx10)/(10xx10)+3/100=30/100+3/100=33/100# and hence
#-0.33=-33/100#
To convert a fraction into percentage, just multiply it by #100# and percentage sign #%#. Hence
#-0.33=-33/100=(-33/100xx100)%=-33%#
