1 13/15.0,75-25%.3 1/5
=28/15.3/4-1/4.16/5
=7/5-4/5
=3/5
=28/15 * 0.75 - 0.25 . 16/5
=1.4 - 0.8
=0.6
\(\dfrac{99}{100}:\left(\dfrac{1}{4}-\dfrac{1}{12}+\dfrac{1}{3}\right)-\left(\dfrac{-7}{5}\right)^2\)
\(\dfrac{13}{15}\cdot0,25\cdot3+\left(\dfrac{8}{15}-1\dfrac{19}{60}\right):1\dfrac{23}{24}\)
Bài 1: Thực hiện phép tính:
1) \(\dfrac{-17}{30}-\dfrac{11}{-15}+\dfrac{-7}{12}\)
2) \(\dfrac{-5}{9}+\dfrac{5}{9}:\left(1\dfrac{2}{3}-2\dfrac{1}{12}\right)\)
3) \(\dfrac{-7}{25}.\dfrac{11}{13}+\dfrac{-7}{25}.\dfrac{2}{13}-\dfrac{18}{25}\)
\(1\dfrac{13}{15}.0,75-\left[\dfrac{11}{20}+25\%\right]:\dfrac{7}{5}\)
Hãy tính các tổng sau:
a)\(\dfrac{1}{1\cdot3}\)+\(\dfrac{1}{3\cdot5}\)+\(\dfrac{1}{5\cdot7}\)+\(\dfrac{1}{7\cdot9}\)+\(\dfrac{1}{9\cdot11}\)=
b)\(\dfrac{1}{4\cdot7}\)+\(\dfrac{1}{7\cdot10}\)+\(\dfrac{1}{10\cdot13}\)+\(\dfrac{1}{13\cdot16}\)=
c)\(\dfrac{1}{2\cdot7}\)+\(\dfrac{1}{7\cdot12}\)+\(\dfrac{1}{12\cdot17}\)+...=
a,\(\dfrac{x}{-3}\text{=}\dfrac{-5}{15}\) b,\(\dfrac{1173}{x}\text{=}\dfrac{3}{5}\)
c,\(\dfrac{2}{x}\text{=}\dfrac{y}{15}\text{=}\dfrac{-25}{75}\)
1, A= \(\dfrac{-3}{4}.\left(0,125-1\dfrac{1}{2}\right):\dfrac{33}{16}-25\%\)
2, B= \(1\dfrac{13}{15}.0,75-\left(\dfrac{11}{20}+25\%\right):\dfrac{7}{3}\)
3, C= \(\dfrac{5}{16}:0,125-\left(2\dfrac{1}{4}-0,6\right).\dfrac{10}{11}\)
4, D= \(6\dfrac{5}{12}:2\dfrac{5}{4}+11\dfrac{1}{4}.\left(\dfrac{1}{3}-\dfrac{1}{5}\right)\)
1. Thực hiện phép tính A=3.\(\dfrac{1}{1\cdot2}\)- 5.\(\dfrac{1}{2\cdot3}\)+7.\(\dfrac{1}{3\cdot4}\)- ... +15\(\dfrac{1}{7\cdot8}\)-17\(\dfrac{1}{8\cdot9}\)
2.Tính tỉ số \(\dfrac{A}{B}\) biết A=\(\dfrac{1}{1\cdot300}\)+\(\dfrac{1}{2\cdot301}\)+\(\dfrac{1}{3\cdot302}\)+...+\(\dfrac{1}{101\cdot400}\) và B=\(\dfrac{1}{1\cdot102}\)+\(\dfrac{1}{2\cdot103}\)+\(\dfrac{1}{3\cdot104}\)+...+\(\dfrac{1}{299\cdot400}\)
Nhanh lên nhé, vội lắm rồi
Bài 1:Tính hợp lí
a)-12,5+17,55-3,5+2,45
b)0,175-(\(2\dfrac{1}{3}\)+0,175)
c)\(\dfrac{5}{13}\).\(\dfrac{-3}{10}\)+\(\dfrac{3}{10}\).\(\dfrac{-8}{13}\)+(-0,7)
Bài 2:Tìm x biết
a)x+\(\dfrac{2}{5}\)=2,4
b)2x-\(\dfrac{4}{5}\)=-1,5
c)11-(15+11)=x-(25-9)
Bài 3:Cho A=\(\dfrac{1}{2^2}\)+\(\dfrac{1}{3^2}\)+\(\dfrac{1}{4^2}\)+\(\dfrac{1}{5^2}\)+....+\(\dfrac{1}{100^2}\)
Chứng tỏ A<1
\(1\dfrac{13}{15}\).0,75-(\(\dfrac{104}{195}\)+25%).\(\dfrac{24}{47}\)-\(3\dfrac{12}{13}\):3
