Thực hiện phép tính:
a) \(\left(\dfrac{9}{25}-2.18\right):\left(3\dfrac{4}{5}+0,2\right)\)
b) \(\dfrac{3}{8}.19\dfrac{1}{3}-\dfrac{3}{8}.33\dfrac{1}{3}\)
c) \(1\dfrac{4}{23}+\dfrac{5}{21}-\dfrac{4}{23}+0,5+\dfrac{16}{21}\)
d) \(\dfrac{21}{47}+\dfrac{9}{45}+\dfrac{26}{47}+\dfrac{4}{5}\)
e) \(\dfrac{15}{12}+\dfrac{5}{13}-\dfrac{3}{12}-\dfrac{18}{13}\)
So sánh
a ) \(\dfrac{7}{15}\text{và}\dfrac{10}{21}\)
b ) \(\dfrac{-3}{200}\text{và}\dfrac{1}{9999}\)
c)\(\dfrac{21}{37}\text{và}\dfrac{199}{188}\)
d)\(\dfrac{-34}{57}\text{và}\dfrac{-343434}{575757}\)
e)\(-3\dfrac{3}{5}\text{và}\dfrac{-16}{5}\)
g) \(\dfrac{-19}{59}\text{và}\dfrac{2009}{-2008}\)
h)\(0,75\text{và}\dfrac{-3}{4}\)
i ) \(\dfrac{5}{4}\text{và}\dfrac{2009}{2008}\)
a)-12= -12/1
b) 2,1= 21/10
c)-7 1/3= -22/3
d)19%= 19/100
a) Tìm số hữu tỉ có dạng \(\dfrac{12}{b}\) sao cho \(\dfrac{-8}{19}< \dfrac{12}{b}< \dfrac{-2}{5}\)
b) Tìm ba phân số có mẫu bằng 5, biết giá trị của mỗi phân số đó lớn hơn \(\dfrac{-6}{7}\) và nhỏ hơn \(\dfrac{-1}{3}\)
a) 12,5.\(\left(-\dfrac{5}{7}\right)+1,5.\left(-\dfrac{5}{7}\right)\)
b) \(\left(-\dfrac{2}{5}-\dfrac{3}{7}\right):\dfrac{4}{5}+\left(-\dfrac{1}{5}+\dfrac{3}{7}\right);\dfrac{4}{5}\)
c) \(12.\left(-\dfrac{2}{3}\right)^2+\dfrac{4}{3}\)
d) \(1:\left(\dfrac{2}{3}-\dfrac{3}{4}\right)^2\)
e) \(15.\left(-\dfrac{2}{3}\right)^{^{ }2}-\dfrac{7}{3}\)
f) \(\dfrac{5^4.20^4}{25^5.4^5}\)
\(\dfrac{0,75+\dfrac{3}{5}-\dfrac{3}{7}-\dfrac{3}{13}}{2,75+2\dfrac{1}{5}-\dfrac{11}{7}-\dfrac{11}{3}}-\dfrac{0,75-\dfrac{3}{11}-\dfrac{1}{3}}{\dfrac{5}{22}-0,625+\dfrac{5}{18}}\)
Tìm x biết:
a) \(\dfrac{x+1}{10}+\dfrac{x+1}{11}+\dfrac{x+1}{12}=\dfrac{x+1}{13}+\dfrac{x+1}{14}\)
b)\(\dfrac{x+4}{2010}+\dfrac{x+3}{2010}=\dfrac{x+2}{2012}+\dfrac{x+1}{2013}\)
Tìm x, biết:
a) \(\dfrac{-3}{7}+x=\dfrac{1}{3}\)
b) \(\dfrac{3}{4}+\dfrac{1}{4}:x=\dfrac{2}{5}\)
c) \(1\dfrac{1}{3}:0,8=\dfrac{2}{3}:0,1x\)
d) \(\left|x-3\right|=\dfrac{1}{2}\)
Thực hiện phép tính :
a ) \(1-\dfrac{1}{2}:\dfrac{-3}{2}+\dfrac{2}{3}\)
b ) \(\dfrac{-3}{4}-\dfrac{-7}{2}+\dfrac{2}{-3}\)
c ) \(0,25-3\dfrac{1}{2}:\dfrac{1}{2}+\dfrac{-3}{4}.\dfrac{2}{-3}\)