[tex]b)\\\\6\dfrac{3}{10}+3\dfrac{4}{5}-3\dfrac{2}{5}+3\dfrac{1}{2}=6\dfrac{3}{10} +\dfrac{2}{5}+3\dfrac{1}{2} = 6\dfrac{3}{10}+\dfrac{4}{10}+3\dfrac{5}{10} = 9\dfrac{12}{10} = 10\dfrac{2}{10} = 10\dfrac{1}{5}[/tex]
[tex]d)\\\\1\dfrac{3}{4}+(99\frac{7}{20}-89\dfrac{2}{5})-1\dfrac{1}{2} =1\dfrac{15}{20}+(99\dfrac{7}{20}-89\dfrac{8}{20})-1\dfrac{10}{20}=\\\\\\=1\dfrac{15}{20}-1\dfrac{10}{20}+(98\dfrac{27}{20}-89\dfrac{8}{20})=\dfrac{5}{20}+9\dfrac{19}{20} = 9\dfrac{24}{20} = 10\dfrac{4}{20} = 10\dfrac{1}{5}[/tex]
