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2/7 + 3/5
= 10/35 + 21/35
= 31/35
31/35 - 2/7
= 31/35 - 10/35
= 21/35
= 3/5
31/35 - 2/5
= 31/35 - 14/35
= 17/35
3/5 + 2/7
= 21/35 + 10/35
= 31/35
2/7 + 3/5 = 10/35 + 21/35 = 31/35
31/35 - 2/7 = 31/35 - 10/35 = 21/35
31/35 - 2/5 = 31/35 - 21/35 = 10/35
3/5 + 2/7 = 21/35 + 10/35 = 31/35
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a) 32x31+69x31-31
=992+2070
=3062
b) 43x166+14x83
=7138+1162
=8300
c) 7/2-3/2:x=5/4
3/2:x=7/2-5/4
3/2:x= 9/4
x=3/2:9/4
x= 2/3
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2/5 x 1/2 : 1/3 = 2/5 x 1/2 x 3 = 3/5
1/2 x 1/3 + 1/4= 1/6 + 1/4 = 4/24 + 6/24 = 10/24 =5/12
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a) \(\dfrac{2}{5}+\dfrac{11}{15}=\dfrac{6}{15}+\dfrac{11}{15}=\dfrac{17}{15}\)
b) \(\dfrac{7}{8}-\dfrac{7}{9}=\dfrac{63}{72}-\dfrac{56}{72}=\dfrac{7}{72}\)
c) \(\dfrac{11}{13}\cdot\dfrac{26}{31}=\dfrac{26}{13}\cdot\dfrac{11}{31}=\dfrac{22}{31}\)
d) \(\dfrac{1}{2}:\dfrac{1}{3}\cdot\dfrac{2}{5}=\dfrac{1}{2}\cdot3\cdot\dfrac{2}{5}=\dfrac{3}{5}\)
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a) = \(\left(\dfrac{2}{7}+\dfrac{4}{7}+\dfrac{1}{7}\right):\dfrac{27}{31}\)
= \(\dfrac{7}{7}\) x \(\dfrac{31}{27}\)
= 1 x \(\dfrac{31}{27}\) = \(\dfrac{31}{27}\)
b) = \(\left(\dfrac{23}{45}:\dfrac{23}{45}\right)\)x \(\dfrac{17}{51}\)
= 1 x \(\dfrac{17}{51}\)= \(\dfrac{17}{51}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
1 + 2 + 3 + 4 + 5 x 1 x 2 x 3 x 4 x 5 + 764 x 31 = 24294
k mình nha
5/3
1/3
2/3
3/2
5/3
1/3
2/3
3/2