Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
Bài 1: Tính
1/ \(\dfrac{-2}{-5}-\left(\dfrac{-4}{3}\right)\)
\(=\dfrac{2}{5}-\left(\dfrac{-4}{3}\right)\)
\(=\dfrac{6}{15}-\left(\dfrac{-20}{15}\right)\)
\(=\dfrac{6-\left(-20\right)}{15}\)
\(=\dfrac{26}{15}\)
2/ \(\left(\dfrac{-2}{4}-\dfrac{1}{2}\right):\dfrac{2}{3}\)
\(=\left(\dfrac{-2}{4}-\dfrac{2}{4}\right):\dfrac{2}{3}\)
\(=-1:\dfrac{2}{3}\)
\(=-1.\dfrac{3}{2}\)
\(=\dfrac{-3}{2}\)
3/ \(\dfrac{5}{12}.\dfrac{17}{11}-\dfrac{5}{12}.\dfrac{7}{11}+\dfrac{5}{12}.\dfrac{1}{11}\)
\(=\dfrac{5}{12}.\left(\dfrac{17}{11}-\dfrac{7}{11}+\dfrac{1}{11}\right)\)
\(=\dfrac{5}{12}.\left(\dfrac{17-7+1}{11}\right)\)
\(=\dfrac{5}{12}.1\)
\(=\dfrac{5}{12}\)
3/7 *14/5 - 1/2 = 6/5-1/2 = 7/10
2/5 - 3/5 *5/10 = 2/5 - 3/10 = 1/10
4/13 *5/11 + 4/13 *6/11 - 4/13
= 4/13*5/11 +4/13 *6/11 - 4/13 *1
= 4/13 *(5/11+ 6/11 - 1)
= 4/13 *0
=0
a) \(\dfrac{3}{5}-\dfrac{3}{5}.\dfrac{2}{3}=\dfrac{3}{5}-\left(\dfrac{3}{5}.\dfrac{2}{3}\right)=\dfrac{3}{5}-\dfrac{2}{5}=\dfrac{1}{5}\)
b) \(\dfrac{-7}{9}.\dfrac{11}{15}-\dfrac{4}{15}.\dfrac{-7}{9}-\dfrac{7}{9}=\dfrac{-7}{9}.\left(\dfrac{11}{15}-\dfrac{4}{15}\right)-\dfrac{7}{9}=\dfrac{-7}{9}.\dfrac{7}{15}-\dfrac{7}{9}=-\dfrac{49}{135}-\dfrac{7}{9}=-\dfrac{154}{135}\)
d) \(3\dfrac{1}{7}-\left(4\dfrac{1}{2}+5\dfrac{3}{7}\right)=\dfrac{22}{7}-\left(\dfrac{9}{2}+\dfrac{38}{7}\right)=\dfrac{22}{7}-\left(\dfrac{63}{14}+\dfrac{76}{14}\right)=\dfrac{22}{7}-\dfrac{139}{14}=\dfrac{44}{14}-\dfrac{139}{14}=-\dfrac{95}{14}\)
\(a,\frac{3}{17}+\frac{-5}{13}+\frac{-18}{35}+\frac{14}{17}+\frac{17}{-35}\)
=\(-\frac{5}{13}+\left(\frac{3}{17}+\frac{14}{17}\right)+\left(\frac{-18}{35}+\frac{-17}{35}\right)\)
= \(-\frac{5}{13}+1+\left(-1\right)\)
=\(-\frac{5}{13}\)
\(b,\frac{-3}{8}.\frac{1}{6}+\frac{3}{-8}.\frac{5}{6}+\frac{-10}{6}\)
=\(\frac{-3}{8}.\left(\frac{1}{6}+\frac{5}{6}\right)+\frac{-10}{6}\)
=\(\frac{-3}{8}.1+\frac{-10}{6}\)
=\(-\frac{49}{24}\)
\(c,\frac{-4}{11}.\frac{5}{15}.\frac{11}{-4}\)
=\(\left(\frac{-4}{11}.\frac{11}{-4}\right).\frac{1}{3}\)
=\(1.\frac{1}{3}=\frac{1}{3}\)
\(d,\frac{13}{8}+\frac{1}{8}:\left(0,75-\frac{1}{2}\right)-25\%.\frac{1}{2}\)
=\(\frac{13}{8}+\frac{1}{8}:\left(\frac{3}{4}-\frac{1}{2}\right)-\frac{1}{4}.\frac{1}{2}\)
=\(\frac{13}{8}+\frac{1}{8}:\frac{1}{4}-\frac{1}{8}\)
=\(\frac{13}{8}+\frac{1}{2}+\frac{-1}{8}\)
=\(\left(\frac{13}{8}+\frac{-1}{8}\right)+\frac{1}{2}\)
=\(\frac{3}{2}+\frac{1}{2}=2\)
\(e,\frac{-1}{2^2}-\left(-2\right)^2-5\)
=\(\frac{-1}{4}-4-5\)
=\(-\frac{37}{4}\)
\(f,\frac{121}{3}-\frac{5}{7}:\left(24-\frac{23}{57}\right)\)
=\(\frac{121}{3}-\frac{5}{7}:\frac{1345}{57}\)
=\(\frac{121}{3}-\frac{57}{1883}\)
\(\approx40,4\)
\(\left(\dfrac{2}{3}-\dfrac{5}{11}+\dfrac{1}{4}\right):\left(1+\dfrac{5}{12}-\dfrac{7}{11}\right)\)
\(=\left(\dfrac{22}{33}-\dfrac{15}{33}+\dfrac{1}{4}\right):\left(1+\dfrac{5}{12}-\dfrac{7}{11}\right)\)
\(=\left(\dfrac{7}{33}+\dfrac{1}{4}\right):\left(\dfrac{12}{12}+\dfrac{5}{12}-\dfrac{7}{11}\right)\)
\(=\left(\dfrac{28}{132}+\dfrac{33}{132}\right):\left(\dfrac{17}{12}-\dfrac{7}{11}\right)=\dfrac{61}{132}:\dfrac{103}{132}\)
\(=\dfrac{61}{132}\times\dfrac{132}{103}=\dfrac{8052}{13596}=\dfrac{61}{103}\)