Đáp án:
\(5)\ \dfrac{-4}{35}\\ 6)\ 0,5\\ 7)\ 2,5\\ 8)\ 2\)
Giải thích các bước giải:
\(5)\ \dfrac{5}{15}+\dfrac{4}{25}-\dfrac{12}{9}+\dfrac{2}{7}+\dfrac{11}{25}\\ =\bigg(\dfrac{4}{25}+\dfrac{11}{25}\bigg)+\bigg(\dfrac{1}{3}-\dfrac{4}{3}\bigg)+\dfrac{2}{7}\\ =\dfrac{3}{5}-1+\dfrac{2}{7}\\ =\dfrac{-4}{35}\\ 6)\ \dfrac{11}{24}-\dfrac{5}{41}+\dfrac{13}{24}+0,5-\dfrac{36}{41}\\ =\bigg(\dfrac{11}{24}+\dfrac{13}{24}\bigg)+\bigg(\dfrac{-5}{41}-\dfrac{36}{41}\bigg)+0,5\\ =1-1+0,5\\ =0,5\\ 7)\ 1\dfrac{4}{23}+\dfrac{5}{21}-\dfrac{4}{23}+0,5+\dfrac{16}{21}\\ =\bigg(1\dfrac{4}{23}-\dfrac{4}{23}\bigg)+\bigg(\dfrac{5}{21}+\dfrac{16}{21}\bigg)+0,5\\ =1+1+0,5=2,5\\ 8)\ \dfrac{7}{5}-\dfrac{5}{4}+\dfrac{1}{3}-\dfrac{3}{4}+\dfrac{8}{5}+\dfrac{2}{3}\\ =\bigg(\dfrac{7}{5}+\dfrac{8}{5}\bigg)+\bigg(\dfrac{-5}{4}-\dfrac{3}{4}\bigg)+\bigg(\dfrac{1}{3}+\dfrac{2}{3}\bigg)\\ =3-2+1\\ =2\)
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