Question

[Dương Thị Quỳnh]

Tính :

a) 3 / 8 + 2 / 5 + 5 / 8

b) 5 / 7 x 2 / 3 x 14 / 15

c) 3 / 8 + 2 / 5 x 5 / 8

d) 11 / 15 - ( 2/ 3 - 1 / 5 )

Answer 1

[Kaxx]

a= 7/5

b=28/63

c=5/8

d=4/15

Answer 2

[_Shadow_]

\(a)\frac{3}{8}+\frac{2}{5}+\frac{5}{8}=\left(\frac{3}{8}+\frac{5}{8}\right)+\frac{2}{5}=1+\frac{2}{5}=\frac{7}{5}\)

\(b)\frac{5}{7}.\frac{2}{3}.\frac{14}{15}=\frac{5.2.14}{7.3.15}=\frac{4}{9}\)

\(c)\frac{3}{8}+\frac{2}{5}.\frac{5}{8}=\frac{3}{8}+\frac{1}{4}=\frac{3}{8}+\frac{2}{8}=\frac{5}{8}\)

\(d)\frac{11}{15}-\left(\frac{2}{3}-\frac{1}{5}\right)=\frac{11}{15}-\frac{7}{15}=\frac{4}{15}\)

~Học tốt~