Odpowiedź:
[tex]a) 1\frac{1}{3}+3\frac{2}{3}=(1+3)+(\frac{1}{3} +\frac{2}{3})=4+1=5\\\\b)-3\frac{2}{7}+7\frac{6}{7}=-(3-\frac{2}{7})+7+\frac{6}{7}=-3-\frac{2}{7}+7+\frac{6}{5} =(-3+7)+(-\frac{2}{7}+\frac{6}{7})=4+\frac{4}{7} \\\\c)2\frac{3}{4}-3\frac{1}{2}=\frac{11}{4}-\frac{7}{2} = -\frac{3}{4}\\\\d)-1\frac{1}{4} -2\frac{2}{3}=-(1\frac{1}{4}+2\frac{2}{3})=-(3+\frac{11}{12})=-3\frac{11}{12}[/tex]
Dziękuję i pozdrawiam.