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a) S
⇒ \(\dfrac{3}{5}+\dfrac{1}{4}=\dfrac{12}{20}+\dfrac{5}{20}=\dfrac{17}{20}\)
b) \(\)Đ
c) Đ
d) S
⇒ \(\dfrac{3}{4}:\dfrac{4}{9}=\dfrac{3}{4}\times\dfrac{9}{4}=\dfrac{27}{16}\)
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a)\(=\dfrac{3}{3}+\dfrac{4}{3}=\dfrac{7}{3}\)
b)\(=\dfrac{5}{9}\times\dfrac{3}{2}=\dfrac{15}{18}=\dfrac{5}{6}\)
d)\(=\left(\dfrac{12}{8}-\dfrac{3}{8}\right)\times2=\dfrac{9}{8}\times2=\dfrac{18}{8}=\dfrac{9}{4}\)
c)\(=\dfrac{4}{3}-\dfrac{5}{6}=\dfrac{8}{6}-\dfrac{5}{6}=\dfrac{3}{6}=\dfrac{1}{2}\)
a) 1 + 4/3 = 7/3
b) 5/9 : 2/3 = 5/6
c ) 4/3 -1/3 x 5/2
= 1 x 5/2
= 5/2
d) ( 3/2 - 3/8) : 1/2
= 9/8 : 1/2
= 9/4
e) 15/16 : 3/8 x 3/4
= 5/2 x 3/4
= 15/8
f) 7/19 x 1/3 x 7/19 x 2/3
= 7/19 x (1/3 x 2/3)
= 7/19 x 2/9
= 14/171
g) 3/5 x 8/27 x 25/3
= 3/5 x 25/3 x 8/27
= 5 x 8/27
= 40/27
h) 1/5 + 4/11 + 4/5 + 7/11
= (1/5 + 4/5) + (4/11 + 7/11)
= 1 + 1
= 2
a ) 5/4 x 2/5 + 1/3 = 2/5 => S
b ) 1/2 x 4 x 1/6 = 1/3 => Đ
c) 2 : 1/3 - 1/2 = 11/2 => Đ
d) 5/2 - 1/3 : 3 = 13/18 => S
a)5/4 x 2/5 +1/3 =2/5=>S
b)1/2 x 4 x 1/6 =1/3=>Đ
c)2 :1/3 -1/2 =11/2=>S
d)5/2 - 1/3 :3 =13/18=>S