Đại số lớp 7

LT

(1-2/3-1/4).(4/5-3/4)

H9
18 tháng 2 lúc 16:21

\(\left(1-\dfrac{2}{3}-\dfrac{1}{4}\right)\cdot\left(\dfrac{4}{5}-\dfrac{3}{4}\right)\)

\(=\left(\dfrac{12}{12}-\dfrac{8}{12}-\dfrac{3}{12}\right)\cdot\left(\dfrac{16}{20}-\dfrac{15}{20}\right)\)

\(=\dfrac{12-8-3}{12}\cdot\dfrac{16-15}{20}\)

\(=\dfrac{1}{12}\cdot\dfrac{1}{20}\)

\(=\dfrac{1}{12\cdot20}\)

\(=\dfrac{1}{240}\)

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