`= -45 \div 18/7-0,5+1,25`
`= -17,5-0,5+1,25`
`= -18+1,25=-16,75`
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Các câu hỏi tương tự
Bài 1: Tính:
a) 10,(3) + 0,(4) - 8,(6)
b) \(\dfrac{0,8:\left(\dfrac{4}{5}.1,25\right)}{0,64-\dfrac{1}{25}}+\dfrac{\left(1,08-\dfrac{2}{25}\right):\dfrac{4}{7}}{\left(6\dfrac{5}{9}-3\dfrac{1}{4}\right).2\dfrac{2}{17}}+\left(1,2.0,5\right):\dfrac{4}{5}\)
1 CM
a, \(\left(\dfrac{1}{1}+\dfrac{1}{3}+\dfrac{1}{5}+...+\dfrac{1}{2n-1}\right)-\left(\dfrac{1}{2}+\dfrac{1}{4}+...+\dfrac{1}{2n}\right)=\dfrac{1}{n+1}+\dfrac{1}{n+2}+...+\dfrac{1}{2n}\)( n∈Z)
b, \(\dfrac{1}{26}+\dfrac{1}{27}+...+\dfrac{1}{50}=\dfrac{99}{50}-\dfrac{97}{49}+...+\dfrac{7}{4}-\dfrac{5}{3}+\dfrac{3}{2}\)
2. thực hiện phép tính
a. \(\dfrac{2}{5}-\dfrac{3}{7}+\dfrac{9}{45}\)
b\(\dfrac{5}{15}+\dfrac{14}{25}-\dfrac{12}{9}+\dfrac{2}{7}+\dfrac{11}{25}\)
c.\(\dfrac{21}{47}+\dfrac{9}{45}+\dfrac{26}{47}+\dfrac{45}{5}\)
Tính tổng sau:
a) \(\dfrac{1}{9}+3,25+5\dfrac{3}{16}+4\dfrac{1}{3}+2,8+0,5\)
b) \(2\dfrac{1}{3}+0,45+4,25+\dfrac{1}{81}+6\dfrac{8}{27}\)
c) \(1,25+2\dfrac{1}{4}+4\dfrac{2}{5}+0,3+2,14+4\dfrac{1}{8}\)
Bài 1: tính
Cho A dfrac{1}{31}+dfrac{1}{32}+dfrac{1}{33}+........+dfrac{1}{60}dfrac{7}{12}
Bdfrac{1}{3^2}+dfrac{1}{3^2}+dfrac{1}{5^2}+.....+dfrac{1}{50^2}
CMR B dfrac{1}{4}; B dfrac{4}{9}
C dfrac{1}{2}.dfrac{3}{4}.dfrac{5}{6}.dfrac{7}{8}...........dfrac{79}{80}dfrac{1}{9}
Đọc tiếp
Bài 1: tính
Cho A= \(\dfrac{1}{31}+\dfrac{1}{32}+\dfrac{1}{33}+........+\dfrac{1}{60}>\dfrac{7}{12}\)
B=\(\dfrac{1}{3^2}+\dfrac{1}{3^2}+\dfrac{1}{5^2}+.....+\dfrac{1}{50^2}\)
CMR B > \(\dfrac{1}{4}\); B < \(\dfrac{4}{9}\)
C = \(\dfrac{1}{2}.\dfrac{3}{4}.\dfrac{5}{6}.\dfrac{7}{8}...........\dfrac{79}{80}\)<\(\dfrac{1}{9}\)
Tìm \(x\)
1. \(\dfrac{1}{7}=\dfrac{8}{-x}\)
2. \(\dfrac{3x}{9}=\dfrac{2}{6}\)
3. \(4\dfrac{2}{5}:\left(\dfrac{-33}{10}\right)+x=-1\dfrac{5}{6}\)
4. \(45\%.x-2\dfrac{3}{8}=-1\dfrac{31}{40}\)
5. \(\left(x-2\dfrac{1}{4}\right):\left(-\dfrac{5}{6}\right)=3\)
a/ Rút gọn 2 biểu thức sau: \(E=\dfrac{\dfrac{1}{99}+\dfrac{2}{98}+\dfrac{3}{97}+...+\dfrac{99}{1}}{\dfrac{1}{2}+\dfrac{1}{3}+\dfrac{1}{4}+...+\dfrac{1}{100}}\)và \(F=\dfrac{94-\dfrac{1}{7}-\dfrac{2}{8}-\dfrac{3}{9}-...-\dfrac{94}{100}}{\dfrac{1}{35}+\dfrac{1}{40}+\dfrac{1}{45}+...+\dfrac{1}{500}}\)
b/ Tính E - 2F
1. thực hiện phép tính
a. dfrac{11}{21}+dfrac{-4}{7}
b. dfrac{5}{15}+dfrac{14}{25}-dfrac{12}{9}+dfrac{2}{7}+dfrac{11}{25}
c. dfrac{2}{3}+dfrac{5}{7}-dfrac{3}{14}
d. dfrac{2}{5}-dfrac{3}{7}+dfrac{9}{45}
e.dfrac{21}{47}+dfrac{9}{45}+dfrac{26}{47}+dfrac{45}{5}
f. dfrac{15}{12}-dfrac{18}{13}+dfrac{5}{13}-dfrac{3}{12}
g. dfrac{-8}{18}-dfrac{15}{27}
h.dfrac{3}{7}+dfrac{-5}{2}-dfrac{3}{5}
i.(dfrac{11}{12}:dfrac{33}{16}).dfrac{3}{5}
Đọc tiếp
1. thực hiện phép tính
a. \(\dfrac{11}{21}\)+\(\dfrac{-4}{7}\)
b. \(\dfrac{5}{15}\)+\(\dfrac{14}{25}\)-\(\dfrac{12}{9}\)+\(\dfrac{2}{7}\)+\(\dfrac{11}{25}\)
c. \(\dfrac{2}{3}\)+\(\dfrac{5}{7}\)-\(\dfrac{3}{14}\)
d. \(\dfrac{2}{5}\)-\(\dfrac{3}{7}\)+\(\dfrac{9}{45}\)
e.\(\dfrac{21}{47}\)+\(\dfrac{9}{45}\)+\(\dfrac{26}{47}\)+\(\dfrac{45}{5}\)
f. \(\dfrac{15}{12}\)-\(\dfrac{18}{13}\)+\(\dfrac{5}{13}\)-\(\dfrac{3}{12}\)
g. \(\dfrac{-8}{18}\)-\(\dfrac{15}{27}\)
h.\(\dfrac{3}{7}\)+\(\dfrac{-5}{2}\)-\(\dfrac{3}{5}\)
i.(\(\dfrac{11}{12}\):\(\dfrac{33}{16}\)).\(\dfrac{3}{5}\)
1. Tìm x, biết:
a, 1dfrac{3}{5} + dfrac{dfrac{2}{7}+dfrac{2}{17}+dfrac{2}{37}}{dfrac{5}{7}+dfrac{5}{17}+dfrac{5}{37}} . x dfrac{16}{5}
b, (dfrac{1}{24.25} + dfrac{1}{25.26} + . . . + dfrac{1}{39.40} ) . 120 + x. dfrac{1}{3} -4
c, left|x-dfrac{1}{3}right| . 2 + dfrac{4}{5} 0,24
d, dfrac{24}{7x-3} dfrac{-4}{25}
e, ( 50% x + 5dfrac{1}{4} ) , dfrac{-2}{3} 2dfrac{5}{6}
f, 1dfrac{1}{3} - 25%dfrac{-5}{12} + 2x 1,6 : dfrac{3}{5}
Đọc tiếp
1. Tìm x, biết:
a, \(1\dfrac{3}{5}\) + \(\dfrac{\dfrac{2}{7}+\dfrac{2}{17}+\dfrac{2}{37}}{\dfrac{5}{7}+\dfrac{5}{17}+\dfrac{5}{37}}\) . x = \(\dfrac{16}{5}\)
b, (\(\dfrac{1}{24.25}\) + \(\dfrac{1}{25.26}\) + . . . + \(\dfrac{1}{39.40}\) ) . 120 + x. \(\dfrac{1}{3}\) = -4
c, \(\left|x-\dfrac{1}{3}\right|\) . 2 + \(\dfrac{4}{5}\) = 0,24
d, \(\dfrac{24}{7x-3}\) = \(\dfrac{-4}{25}\)
e, ( 50% x + \(5\dfrac{1}{4}\) ) , \(\dfrac{-2}{3}\) = \(2\dfrac{5}{6}\)
f, \(1\dfrac{1}{3}\) - 25%\(\dfrac{-5}{12}\) + 2x = 1,6 : \(\dfrac{3}{5}\)