a. \(-3\dfrac{3}{4}+\dfrac{-10}{25}+\dfrac{-6}{12}\)

= \(\dfrac{-9}{4}+\dfrac{-10}{25}+\dfrac{-6}{12}\)

= \(\dfrac{-675}{300}+\dfrac{-120}{300}+\dfrac{-150}{300}\)

= \(\dfrac{-675+\left(-120\right)+\left(-150\right)}{300}\)

= \(\dfrac{-945}{300}=\dfrac{-63}{20}\)

b. \(4-1\dfrac{2}{5}-\dfrac{8}{3}\)

= \(4-\dfrac{7}{5}-\dfrac{8}{3}\)

= \(\dfrac{60}{15}-\dfrac{21}{15}-\dfrac{40}{15}\)

= \(\dfrac{60-21-40}{15}\)

= \(\dfrac{-1}{15}\)

c. \(-\dfrac{5}{12}+1\dfrac{5}{18}-2,25\)

= \(\dfrac{-5}{12}+\dfrac{23}{18}-2,25\)

= \(\dfrac{-15}{36}+\dfrac{46}{36}-\dfrac{81}{36}\)

= \(\dfrac{-15+46+81}{36}\)

= \(\dfrac{112}{36}=\dfrac{28}{9}\)

???

Bn chia câu ra cho mn dễ làm

612220032 . 324

= 1983592904.10¹¹

đề cũng hơi khó hiểu

x là nhân ak bn

Nhan đề này có trong SGK lớp 8 rồi mà 

oh

ok