Question

1, tính

a, 2⁵ + 8 [(-2)³ : \(\dfrac{1}{2}\)]⁰ - (\(\dfrac{1}{2}\))³ . 2 + (-2)³

b, \(\dfrac{7}{15}-\dfrac{9}{19}-\dfrac{-8}{15}-\dfrac{10}{19}\)

c, \(1\dfrac{1}{3}\div\dfrac{4}{5}+2\dfrac{2}{3}\div\dfrac{4}{5}\)

Answer 1

b) \(\dfrac{7}{15}-\dfrac{9}{19}\)\(-\dfrac{-8}{15}-\dfrac{10}{19}\)
=\(\left(\dfrac{7}{15}-\dfrac{8}{15}\right)\) \(-\left(\dfrac{9}{19}-\dfrac{10}{19}\right)\)
= \(-\dfrac{1}{15}\) - \(\left(-\dfrac{1}{19}\right)\)
\(=-\dfrac{1}{15}\) + \(\dfrac{1}{19}\)

= \(-\dfrac{4}{285}\)

Answer 2

c) \(1\dfrac{1}{3}\) \(\div\) \(\dfrac{4}{5}\) + 2\(\dfrac{2}{3}\) \(\div\)\(\dfrac{4}{5}\)
= \(\left(1\dfrac{1}{3}+2\dfrac{2}{3}\right)\) \(\div\dfrac{4}{5}\)
= \(\left[\left(1+2\right)+\left(\dfrac{1}{3}+\dfrac{2}{3}\right)\right]\) \(\div\dfrac{4}{5}\)
= ( 3 + 1 ) \(\div\dfrac{4}{5}\)
= 4 \(\div\dfrac{4}{5}\)
= \(\dfrac{4.5}{4}\)
= 5