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c.
\(\frac{1}{3}\times\frac{5}{7}-\frac{7}{27}\times\frac{36}{14}\)
\(=\frac{1}{3}\times\frac{5}{7}-\frac{7}{3\times9}\times\frac{4\times9}{7\times2}\)
\(=\frac{1}{3}\times\frac{5}{7}-\frac{1}{3}\times\frac{4}{6}\)
\(=\frac{1}{3}\times\left(\frac{5}{7}-\frac{4}{6}\right)\)
\(=\frac{1}{3}\times\left(\frac{30-38}{42}\right)\)
\(=\frac{1}{3}\times\frac{-8}{42}\)
\(=-\frac{4}{63}\)
Chúc bạn học tốt
\(a,\)\(\frac{1}{2}.\left(\frac{2}{9}+\frac{3}{7}-\frac{5}{37}\right)\)
\(\Rightarrow\frac{1}{2}.\left(\frac{2.259}{2331}+\frac{3.333}{2331}-\frac{5.63}{2331}\right)\)
\(\Rightarrow\frac{1}{2}.\left(\frac{518}{2331}+\frac{999}{2331}-\frac{315}{2331}\right)\)
\(\Rightarrow\frac{1}{2}.\left(\frac{518+999-315}{2331}\right)\)
\(\Rightarrow\frac{1}{2}.\frac{1202}{2331}\)
\(\Rightarrow\frac{601}{2331}\)
\(b,\)\(\left(-\frac{5}{28}+1,75+\frac{8}{35}\right):\left(-3\frac{9}{20}\right)\)
\(\Rightarrow\frac{9}{5}:\left(-\frac{69}{20}\right)\)
\(=-\frac{12}{23}\)
\(c,\)\(\frac{1}{3}.\frac{1}{5}-\frac{7}{27}.\frac{36}{14}\)
\(=\frac{1}{15}-\frac{2}{3}\)
\(=\frac{1}{15}-\frac{10}{15}=-\frac{9}{15}=-\frac{3}{5}\)
\(d,\)\(70,5-528:\frac{15}{2}\)
\(=70,5-\frac{352}{5}\)
\(=\frac{1}{10}\)
1. a) \(\frac{-2}{7}+\frac{15}{23}+\frac{\left(-15\right)}{17}+\frac{4}{19}+\frac{8}{23}\)
\(=\left(\frac{-2}{7}+\frac{-5}{7}\right)+\left(\frac{15}{23}+\frac{8}{23}\right)+\frac{4}{19}\)
\(=\left(-1\right)+1+\frac{4}{19}\)
\(=0+\frac{4}{19}=\frac{4}{19}\)
b) \(\frac{7}{19}\cdot\frac{8}{11}+\frac{7}{19}\cdot\frac{3}{11}+\frac{12}{19}\)
\(=\frac{7}{19}\cdot\left(\frac{8}{11}+\frac{3}{11}\right)+\frac{12}{19}\)
\(=\frac{7}{19}\cdot1+\frac{12}{19}\)
\(=\frac{7}{19}+\frac{12}{19}=\frac{19}{19}=1\)
2. a) \(\frac{1}{3}+\frac{\left(-2\right)}{16}-\frac{7}{14}\)
\(=\frac{5}{24}-\frac{1}{2}\)
\(=-\frac{7}{24}\)
b) \(11\frac{3}{13}-2\frac{4}{7}+5\frac{3}{13}\)
\(=\left(11-2+5\right)+\frac{3}{13}-\frac{4}{7}+\frac{3}{13}\)
\(=14+\left(-\frac{10}{91}\right)\)
\(=-14\frac{10}{91}\)
c) \(0,7\cdot2\frac{2}{3}\cdot20\cdot0,375\cdot\frac{5}{28}\)
\(=\frac{7}{10}\cdot\frac{8}{3}\cdot20\cdot\frac{3}{8}\cdot\frac{5}{28}\)
\(=\left(\frac{7}{10}\cdot\frac{5}{28}\right)\cdot\left(\frac{8}{3}\cdot\frac{3}{8}\right)\cdot20\)
\(=\frac{1}{8}\cdot1\cdot20\)
\(=\frac{20}{8}=\frac{5}{2}\)
d) \(\frac{6}{7}+\frac{5}{7}:5-\frac{8}{9}\)
\(=\frac{6}{7}+\frac{1}{7}-\frac{8}{9}\)
\(=1-\frac{8}{9}\)
\(=\frac{1}{9}\)
~Học tốt~
Trả lời
b)(1/3+12/67+13/41)-(79/67-28/41)
=1/3+12/67+13/41-79/67+28/41
=1/3+(12/67-79/67)+(13/41+28/41)
=1/3+(-67/67)+41/41
=1/3+(-1)+1
=1/3+0
=1/3.
mk muốn xem bài của mk đúng hay sai thôi !
chứ làm thì mk làm xong rồi !
â, -4/9(7/15+8/15)=-4/9
b,-5/4(16/25+9/25)=-5/4
,.....
dài quá mik làm ko hết
hok tốt
a) \(\frac{28}{29}-\frac{27}{28}=\frac{784}{812}-\frac{783}{812}=\frac{784-783}{812}=\frac{1}{812}\)
b) \(\frac{23}{8}-\frac{7}{2}=\frac{23}{8}-\frac{28}{8}=\frac{23-28}{8}=\frac{-5}{8}\)
c) \(\frac{11}{15}-\frac{3}{5}=\frac{11}{15}-\frac{9}{15}=\frac{11-9}{15}=\frac{2}{15}\)
a, mẫu số chung là 203
b, mẫu chung là 8
c, mẫu chung là 15
tự quy đồng mẫu rồi tính. dễ mà