-1.55 = - 1 55/100
= - 1 11/20
You'll have to write it over 100, since it has 2 decimal places:
[tex] - \frac{155}{100} [/tex] = [tex] - \frac{31}{20} [/tex] = [tex] - 1 \frac{11}{20} [/tex]
Hope it helped,
BioTeacher101