buổi sáng bán được số xe máy là :

\(60\times\dfrac{3}{20}=9\) ( chiếc )

buổi chiều bán được số xe máy là :

\(\left(60-9\right)\times\dfrac{5}{17}=15\) ( chiếc )

cửa hàng còn lại số xe máy là :

\(60-9-15=36\)

input : 2 số a, b

output : giá trị tổng 2 số a,b

-17/45

c

có : \(25\times x=15\times30\)

\(25\times x=450\)

\(x=450\div25\)

\(x=18\)

Lần 1 bác lấy số thóc là :

28040 : 2 = 14020 ( kg thóc )

Lần 2 bác lấy số thóc là :

14020 + 1205 = 15225 ( kg thóc )

951

g. \(-\dfrac{2}{3}\times\dfrac{4}{5}+\dfrac{1}{5}\div\dfrac{9}{11}=-\dfrac{8}{15}+\dfrac{1}{5}\times\dfrac{11}{9}=-\dfrac{8}{15}+\dfrac{11}{45}=\dfrac{24}{45}+\dfrac{11}{45}=\dfrac{35}{45}=\dfrac{7}{9}\)

h.

\(\left(-6,2\div2+3,7\right)\div0,2=\left(-3,1+3,7\right)\div0,2=0,6\div0,2=3\)

k.

\(\dfrac{2}{3}+\dfrac{1}{5}\times\dfrac{10}{7}=\dfrac{2}{3}+\dfrac{10}{35}=\dfrac{2}{3}+\dfrac{2}{7}=\dfrac{14}{21}+\dfrac{6}{21}=\dfrac{20}{21}\)

m.

\(\dfrac{2}{7}+\dfrac{5}{7}\times\dfrac{14}{25}=\dfrac{2}{7}+\dfrac{1\times2}{1\times5}=\dfrac{2}{7}+\dfrac{2}{5}=\dfrac{10}{35}+\dfrac{14}{35}=\dfrac{24}{35}\)

a) \(\dfrac{3}{4}+\dfrac{-1}{3}+\dfrac{-5}{18}=\dfrac{3}{4}+\left(\dfrac{-1}{3}+\dfrac{-5}{18}\right)=\dfrac{3}{4}+\left(\dfrac{-6}{18}+\dfrac{-5}{18}\right)=\dfrac{3}{4}+\dfrac{-11}{18}=\dfrac{27}{36}+\dfrac{-22}{36}=\dfrac{5}{36}\)

b) \(13,57\times5,5+13,57\times3,5+13,57=13,57\times\left(5,5+3,5+1\right)=13,57\times10=135,7\)

a)\(\dfrac{1}{3}+\dfrac{3}{4}-\dfrac{5}{6}=\dfrac{4}{12}+\dfrac{9}{12}-\dfrac{10}{12}=\dfrac{3}{12}=\dfrac{1}{4}\)

b)\(\dfrac{-2}{3}+\dfrac{6}{5}\div\dfrac{2}{3}-\dfrac{2}{15}=\dfrac{-2}{3}+\dfrac{9}{5}-\dfrac{2}{15}=\dfrac{-10}{15}+\dfrac{27}{15}-\dfrac{2}{15}=\dfrac{15}{15}=1\)

c)\(\dfrac{-3}{7}+\dfrac{5}{13}+\dfrac{-4}{7}=(\dfrac{-3}{7}+\dfrac{-4}{7})+\dfrac{5}{13}=\dfrac{-7}{7}+\dfrac{5}{13}=-1+\dfrac{5}{13}=\dfrac{-13}{13}+\dfrac{5}{13}=\dfrac{-8}{13}\)

d)\(\dfrac{12}{19}+\dfrac{-8}{13}-\dfrac{12}{19}+\dfrac{5}{-13}+2=(\dfrac{12}{19}-\dfrac{12}{19})+(\dfrac{-8}{13}+\dfrac{-5}{13})+2=0+\dfrac{-13}{13}+2=0+\left(-1\right)+2=1\)