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a, 3 \(\frac{14}{19}\)+ \(\frac{13}{17}\)+ \(\frac{35}{43}\)+ 6\(\frac{5}{19}\)+ \(\frac{8}{43}\)= \(\left(3\frac{14}{19}+6\frac{5}{19}\right)+\left(\frac{35}{43}+\frac{8}{43}\right)+\frac{13}{17}=\)\(9+1+\frac{13}{17}=8+\frac{13}{17}=8\frac{13}{17}\)
b, \(\frac{-5}{7}.\frac{2}{11}+\frac{-5}{7}.\frac{9}{11}+1\frac{5}{7}\)\(=\frac{-5}{7}\left(\frac{2}{11}+\frac{9}{11}\right)+1\frac{5}{7}\)\(=\frac{-5}{7}.1+1\frac{5}{7}\)\(=\frac{-5}{7}+\frac{12}{7}=\frac{7}{7}=1\)
Chúc bn học tốt
\(3\frac{14}{19}+\frac{13}{17}+\frac{35}{43}+6\frac{5}{19}+\frac{8}{43}\)
\(=\left(3\frac{14}{19}+6\frac{5}{19}\right)+\left(\frac{35}{43}+\frac{8}{43}\right)+\frac{13}{17}\)
\(=10+1+\frac{13}{17}=11+\frac{13}{17}=11\frac{13}{17}\)
a) =(8/15+17/30)-9/10
=(16/30+17/30)-9/10
=33/30+9/10
=11/10+9/10
=20/10=2
b)11/14.(-25/49) {câu đay mk hk tính nhah đk)
c)=13/7.(9/20+11/20)-15/7
=13/7.1-15/7
=13/7-15/7
=(-2)
b) \(\frac{11}{14}:\frac{-25}{49}=\frac{11}{14}.\frac{49}{-25}=\frac{11.7.7}{2.7.\left(-25\right)}=\frac{11.7}{2.\left(-25\right)}=\frac{-77}{50}\)
M=3/1.2-5/2.3+7/3.4-9/4.5+11/5.6-13/6.7+15/7.8+17/8.9
=(1/1.1+2/1.2)-(2/2.3+3/2.3)+(3/3.4+4/3.4)-(4/4.5+5/4.5)+...+(8/8.9+9/8.9)(phần ... là làm tương tự nhé)
=1/2+1-(1/3+1/2)+(1/4+1/3)-(1/5+1/4)+...+(1/9+1/8)(phần ... là làm tương tự nhé)
=1+(1/2-1/2)+(1/3-1/3)+(1/4-1/4)+...+(1/8-1/8)-1/9
=1+0+0+0+...+0-1/9
=1-1/9
=8/9
a) \(\frac{-5}{8}\cdot\left(\frac{4}{9}+\frac{-7}{12}\right)\)
\(=\frac{-5}{8}\cdot\frac{-5}{36}\)
\(=\frac{25}{288}\)
b) \(\left(-3,2\right)\cdot\frac{-15}{64}+\left(0,8-2\frac{4}{5}\right):3\frac{1}{2}\)
\(=\frac{3}{4}+\left(-2\right):\frac{7}{2}\)
\(=\frac{3}{4}+\frac{-4}{7}\)
\(=\frac{5}{28}\)
=))
Bài 1:
\(g.\frac{5}{11}+\frac{6}{11}=\frac{5+6}{11}=\frac{11}{11}=1\)\(\)
\(e.\frac{-17}{25}.\frac{20}{33}+\frac{-17}{25}.\frac{13}{33}+\frac{-3}{25}=\frac{-17}{25}.\left(\frac{20}{33}+\frac{13}{33}\right)+\frac{-3}{25}\)
\(=\frac{-17}{25}.1+\frac{-3}{25}=\frac{-17}{25}+\frac{-3}{25}=\frac{-17-3}{25}=\frac{-20}{25}=\frac{-4}{5}\)
\(d.\frac{5}{7}.\frac{19}{23}+\frac{5}{7}.\frac{5}{23}-\frac{5}{7}.\frac{1}{23}=\frac{5}{7}\left(\frac{19}{23}+\frac{5}{23}-\frac{1}{23}\right)\)
\(=\frac{5}{7}\left(\frac{19+5-1}{23}\right)=\frac{5}{7}.1=\frac{5}{7}\)
\(c.\left(-11\right).\frac{9}{22}=\frac{\left(-11\right).9}{22}=\frac{-99}{22}=\frac{-9}{2}\)
\(b.\frac{5}{6}-\frac{1}{8}=\frac{5.4}{6.4}-\frac{1.3}{8.3}=\frac{20}{24}-\frac{3}{24}=\frac{17}{24}\)
\(a.\frac{2}{3}+\frac{1}{5}-\frac{1}{6}=\frac{2.10}{3.10}+\frac{1.6}{5.6}-\frac{1.5}{6.5}=\frac{20}{30}+\frac{6}{30}-\frac{5}{30}\)
\(=\frac{20+6-5}{30}=\frac{21}{30}=\frac{7}{10}\)
Bài 2:
\(a.\frac{3}{4}+x=\frac{11}{12}\)
\(\Leftrightarrow x=\frac{11}{12}-\frac{3}{4}\)
\(\Leftrightarrow x=\frac{11}{12}-\frac{9}{12}\)
\(\Leftrightarrow x=\frac{2}{12}=\frac{1}{6}\)
\(b.x-\frac{11}{12}=0,5\)
\(\Leftrightarrow x=\frac{1}{2}-\frac{11}{12}\)
\(\Leftrightarrow x=\frac{6}{12}+\frac{11}{12}\)
\(\Leftrightarrow x=\frac{17}{12}\)
\(S=\frac{3}{2}-\frac{5}{6}+\frac{7}{12}-\frac{9}{20}+\frac{11}{30}-\frac{13}{42}+\frac{15}{56}-\frac{17}{72}\)
\(S=\frac{3}{1.2}-\frac{5}{2.3}+\frac{7}{3.4}-\frac{9}{4.5}+\frac{11}{5.6}-\frac{13}{6.7}+\frac{15}{7.8}-\frac{17}{8.9}\)
\(S=3\left(\frac{1}{1.2}\right)-5\left(\frac{1}{2.3}\right)+7\left(\frac{1}{3.4}\right)-9\left(\frac{1}{4.5}\right)+11\left(\frac{1}{5.6}\right)-13\left(\frac{1}{6.7}\right)+15\left(\frac{1}{7.8}\right)-17\left(\frac{1}{8.9}\right)\)
\(S=3\left(1-\frac{1}{2}\right)-5\left(\frac{1}{2}-\frac{1}{3}\right)+7\left(\frac{1}{3}-\frac{1}{4}\right)-9\left(\frac{1}{4}-\frac{1}{5}\right)+11\left(\frac{1}{5}-\frac{1}{6}\right)-13\left(\frac{1}{6}-\frac{1}{7}\right)+15\left(\frac{1}{7}-\frac{1}{8}\right)-17\left(\frac{1}{8}-\frac{1}{9}\right)\)
\(S=\left(3-\frac{3}{2}\right)-\left(\frac{5}{2}-\frac{5}{3}\right)+\left(\frac{7}{3}-\frac{7}{4}\right)-\left(\frac{9}{4}-\frac{9}{5}\right)+\left(\frac{11}{5}-\frac{11}{6}\right)-\left(\frac{13}{6}-\frac{13}{7}\right)+\left(\frac{15}{7}-\frac{15}{8}\right)-\left(\frac{17}{8}-\frac{17}{9}\right)\)\(S=3-\frac{3}{2}-\frac{5}{2}+\frac{5}{3}+\frac{7}{3}-\frac{7}{4}-\frac{9}{4}+\frac{9}{5}+\frac{11}{5}-\frac{11}{6}-\frac{13}{6}+\frac{13}{7}+\frac{15}{7}-\frac{15}{8}-\frac{17}{8}+\frac{17}{9}\) Giờ bạn chỉ cần nhóm từng cặp phân số có cùng tử số rồi tính tiếp là ra kết quả thôi
( khi nhóm cặp nhớ đổi dấu nha)
-17/30 - 11/-15 + -7/12
= -34/60 - -44/60 + -35/60
= -25/60
= -5/12