Question

[Nguyễn Thị Gia Linh]

  

Answer 1

[Nguyễn Lê Phước Thịnh]

Câu 1: B

Câu 2: D

Câu 3: B

Câu 4: C

Câu 5: A

Câu 6: B

Câu 7: C

Câu 8: B

Câu 9: C

Câu 10: D

Câu 11: D

Câu 12: C

Bài 1:

a: \(\dfrac{7}{30}+\dfrac{-12}{37}+\dfrac{23}{30}+\dfrac{-25}{37}\)

\(=\left(\dfrac{7}{30}+\dfrac{23}{30}\right)+\left(-\dfrac{12}{37}-\dfrac{25}{37}\right)\)

\(=\dfrac{30}{30}+\dfrac{-37}{37}=1-1=0\)

b: \(\dfrac{-20}{23}+\dfrac{8}{15}-\dfrac{3}{23}+\dfrac{7}{15}+\dfrac{1}{2}\)

\(=\left(-\dfrac{20}{23}-\dfrac{3}{23}\right)+\left(\dfrac{8}{15}+\dfrac{7}{15}\right)+\dfrac{1}{2}\)

\(=-1+1+\dfrac{1}{2}=\dfrac{1}{2}\)

c: \(\left(-12,5\right)+17,55+\left(-3,5\right)+2,45\)

\(=\left(-12,5-3,5\right)+\left(17,55+2,45\right)\)

=20-16

=4

d: \(\left(-9,237\right)+3,8+1,237-3,8+1,123\)

\(=\left(-9,237+1,237\right)+\left(3,8-3,8\right)+1,123\)

=-8+1,123

=-6,877

e: \(4,35-\left(2,67-1,65\right)+\left(3,54-6,33\right)\)

\(=4,35-2,67+1,65+3,54-6,33\)

\(=6-9+3,54=3,54-3=0,54\)

g: \(\dfrac{5}{7}\cdot\dfrac{5}{11}+\dfrac{5}{7}\cdot\dfrac{2}{11}-\dfrac{5}{7}\cdot\dfrac{14}{11}\)

\(=\dfrac{5}{7}\left(\dfrac{5}{11}+\dfrac{2}{11}-\dfrac{14}{11}\right)=\dfrac{5}{7}\cdot\dfrac{-7}{11}=-\dfrac{5}{11}\)

h: \(\dfrac{-5}{7}\cdot\dfrac{3}{13}+\dfrac{-5}{7}\cdot\dfrac{10}{13}+1\dfrac{5}{7}\)

\(=-\dfrac{5}{7}\left(\dfrac{3}{13}+\dfrac{10}{13}\right)+\dfrac{12}{7}=-\dfrac{5}{7}+\dfrac{12}{7}=\dfrac{7}{7}=1\)

i: \(3,58\cdot24,45+3,58\cdot75,55+12,42\)

\(=3,58\left(24,45+75,55\right)+12,42\)

\(=358+12,42=370,42\)

k: \(3,4\cdot\left(-23,68\right)-3,4\cdot45,12+\left(-31,2\right)\cdot3,4\)

\(=3,4\left(-23,68-45,12-31,2\right)\)

\(=3,4\cdot\left(-100\right)=-340\)

l: \(1,14\cdot6,4+1,14\cdot3,6+11,4\)

\(=1,14\left(6,4+3,6\right)+1,14\cdot10\)

\(=1,14\cdot20=22,8\)

Answer 2

[Nguyễn Thị Gia Linh]

Giúp mk với!