Răspuns:
a)
[tex]-\frac{5}{3} -\frac{2}{3}=\frac{-5-2}{3}=-\frac{7}{3}[/tex]
[tex]1\frac{2}{3}-\frac{1}{3}=\frac{5}{3}-\frac{1}{3}=\frac{5-1}{3}=\frac{4}{3}[/tex]
[tex]6,78-5,07=\frac{678}{100} -\frac{507}{100}=\frac{678-507}{100}=\frac{171}{100}=1,71[/tex]
b)
[tex]\frac{7}{4} -\frac{9}{20}=\frac{35}{20} -\frac{9}{20}=\frac{35-9}{20}=\frac{26}{20}=\frac{13}{10}[/tex]
[tex]-\frac{31}{12} -\frac{4}{3} =-\frac{31}{12} -\frac{16}{12} =\frac{-31-16}{12}=-\frac{47}{12}[/tex]
[tex]0,(2)+0,(3)=\frac{2}{9} +\frac{3}{9}=\frac{2+3}{9}=\frac{5}{9}[/tex]
[tex]7,(2)+2,(3)+2,(79)=\frac{72-7}{9} +\frac{23-2}{9} +\frac{279-2}{99} =\frac{65}{9} +\frac{21}{9} +\frac{277}{99}=\frac{715}{99} +\frac{231}{99} +\frac{279}{99}=\frac{715+231+279}{99}=\frac{1225}{99}[/tex]
c)
[tex]\frac{5}{13} *\frac{26}{15}=\frac{1}{1} *\frac{2}{5}=\frac{2}{5}[/tex]
[tex]\frac{7}{10} *\frac{10}{7}=\frac{1}{1} *\frac{1}{1} =1[/tex]
d)[tex]\frac{2}{3} :\frac{5}{6}=\frac{2}{3} *\frac{6}{5}=\frac{2}{1} *\frac{2}{5} =\frac{4}{5}[/tex]
