Question

Câu 1. Thực hiện phép tính ( tính hợp lí nếu có thể ):

c) \(\dfrac{1}{7}\) . \(\dfrac{-2}{3}\) + \(\dfrac{-1}{7}\) . \(\dfrac{8}{3}\) + \(\dfrac{1}{7}\)

d) \(\dfrac{1}{2}\) . \(\left(\dfrac{1}{5}\right)^0\) + \(\dfrac{-3}{4}\) : ( -0,2 )²

Answer 1

\(c,\dfrac{1}{7}.\dfrac{-2}{3}+\dfrac{-1}{7}.\dfrac{8}{3}+\dfrac{1}{7}\)
\(=\dfrac{1}{7}.\left(\dfrac{-2}{3}-\dfrac{8}{3}+1\right)\)
\(=\dfrac{1}{7}.\left(\dfrac{-10}{3}+\dfrac{3}{3}\right)\)
\(=\dfrac{1}{7}.\dfrac{-7}{3}\)
\(=\dfrac{-1}{3}\)
\(d,\dfrac{1}{2}.\left(\dfrac{1}{5}\right)^0+\dfrac{-3}{4}:\left(-0,2\right)^2\)
\(=\dfrac{1}{2}.1-\dfrac{3}{4}:\dfrac{1}{25}\)
\(=\dfrac{1}{2}-\dfrac{3}{4}.25\)
\(=\dfrac{1}{2}-\dfrac{75}{4}\)
\(=\dfrac{2}{4}-\dfrac{75}{4}\)
\(=\dfrac{-73}{4}\)

Answer 2

c.

\(=\dfrac{1}{7}.\dfrac{-2}{3}+\dfrac{1}{7}.\dfrac{-8}{3}+\dfrac{1}{7}\)

\(=\dfrac{1}{7}.\left(\dfrac{-2}{3}+\dfrac{-8}{3}+1\right)\)

\(=\dfrac{1}{7}.\dfrac{-7}{3}\)

\(=-\dfrac{1}{3}\)

d.

\(\dfrac{1}{2}.\left(\dfrac{1}{5}\right)^0+\dfrac{-3}{4}:\left(-0,2\right)^2\)

\(=\dfrac{1}{2}.1+\dfrac{-3}{4}:\left(0,04\right)\)

\(=\dfrac{1}{2}-\dfrac{75}{4}\)

\(=-\dfrac{73}{4}\)