[Risolto] N. 228

228)

$\frac{5}{4}-\big(\frac{2}{5}-\frac{3}{4}\big)-\big(2-\frac{2}{8}\big)+\big(-3+\frac{9}{5}\big)$=

=$\frac{5}{4}-\big(\frac{8-15}{20}\big)-\big(2-\frac{1}{4}\big)+\big(\frac{-15+9}{5}\big)$=

=$\frac{5}{4}-\big(-\frac{7}{20}\big)-\big(\frac{8-1}{4}\big)+\big(-\frac{6}{5}\big)$=

=$\frac{5}{4}+\frac{7}{20}-\frac{7}{4}-\frac{6}{5}$=

=$\frac{25+7-35-24}{20}$=

=$-\frac{27}{20}$

5/4-(2/5-3/4)-(2-2/8)+(-3+9/5)=

= 5/4-((8-15)/20)-14/8+(-6/5) =

=5/4+7/20-7/4-6/5 =

= (25+7-35-24)/20 = -27/20