Question

1 thực hiện phép tính(tính nhanh nếu có thể)

\(\left(7\dfrac{1}{3}-\dfrac{1}{3}\right):\dfrac{1}{7}\)

\(\dfrac{-1}{3}.\left(\dfrac{-15}{17}\right).\dfrac{34}{45}\) c,\(\dfrac{1}{2}.\dfrac{6}{5}-\dfrac{1}{5}.\dfrac{1}{2}\)

Answer 1

a) \(\left(7\dfrac{1}{3}-\dfrac{1}{3}\right):\dfrac{1}{7}\)

\(=\left(\dfrac{22}{3}-\dfrac{1}{3}\right):\dfrac{1}{7}\)

\(=7:\dfrac{1}{7}=7.7=49\)

b) \(\dfrac{-1}{3}.\left(\dfrac{-15}{17}\right).\dfrac{34}{45}\)

\(=\dfrac{-1}{3}.\left(\dfrac{-15}{17}.\dfrac{34}{45}\right)\)

\(=\dfrac{-1}{3}.\dfrac{-2}{3}=\dfrac{2}{9}\)

c)\(\dfrac{1}{2}.\dfrac{6}{5}-\dfrac{1}{5}.\dfrac{1}{2}\)

\(=\dfrac{1}{2}.\left(\dfrac{6}{5}-\dfrac{1}{5}\right)\)

\(=\dfrac{1}{2}.1\)

\(=\dfrac{1}{2}\)

Answer 2

c) \(\frac{1}{2}.\frac{6}{5} - \frac{1}{5}.\frac{1}{2}\)

\(= \frac{1}{2}\left. ( \frac{6}{5} - \frac{1}{5}\right )\)

= \(\frac{1}{2}.1 = \frac{1}{2}\)