Bài làm
a) \(\frac{7}{60}+\frac{-3}{40}+\frac{-11}{30}\)
\(=\frac{14}{120}+\frac{-9}{120}+\frac{-44}{120}\)
\(=\frac{14-9-44}{120}\)
\(=-\frac{39}{120}=-\frac{13}{40}\)
b) \(\frac{1}{2}+\frac{1}{3}+\frac{1}{5}\)
\(=\frac{15}{30}+\frac{10}{30}+\frac{6}{30}\)
\(=\frac{31}{30}\)
c) \(-\frac{4}{7}+\frac{8}{9}+\frac{-10}{21}\)
\(=\frac{-36}{63}+\frac{56}{63}+\frac{-30}{63}\)
\(=\frac{-10}{63}\)
\(\frac{7}{60}+\left(-\frac{3}{40}\right)+\left(-\frac{11}{30}\right)\)
Đặt \(MSC=120\)
\(\frac{7}{60}+\left(-\frac{3}{40}\right)+\left(-\frac{11}{30}\right)=\frac{14}{120}+\left(\frac{-9}{120}\right)+\left(\frac{-44}{120}\right)=\frac{14+\left(-9\right)+\left(-44\right)}{120}=\frac{-39}{120}\)
\(\frac{1}{2}+\frac{1}{3}+\frac{1}{5}\)
Đặt \(MSC=30\)
\(\frac{1}{2}+\frac{1}{3}+\frac{1}{5}=\frac{15}{30}+\frac{10}{30}+\frac{6}{30}=\frac{15+10+6}{30}=\frac{31}{30}\)
\(\left(-\frac{4}{7}\right)+\frac{8}{9}+\left(-\frac{10}{21}\right)\)
Đặt \(MSC=63\)
\(\left(-\frac{4}{7}\right)+\frac{8}{9}+\left(-\frac{10}{21}\right)=\left(\frac{-36}{63}\right)+\frac{56}{63}+\left(\frac{-30}{63}\right)=\frac{\left(-36\right)+56+\left(-30\right)}{63}=-\frac{10}{63}\)
1) \(\frac{7}{60}+\left(-\frac{3}{40}\right)+\left(-\frac{11}{30}\right)=\frac{14}{120}+\left(-\frac{9}{120}\right)+\left(-\frac{44}{120}\right)=-\frac{39}{120}=-\frac{13}{40}\)
2) \(\frac{1}{2}+\frac{1}{3}+\frac{1}{5}=\frac{15}{30}+\frac{10}{30}+\frac{6}{30}=\frac{31}{30}\)
3) \(-\frac{4}{7}+\frac{8}{9}+\left(-\frac{10}{21}\right)=-\frac{36}{63}+\frac{56}{63}+\left(-\frac{30}{63}\right)=-\frac{10}{63}\)
\(A)MSC:240\)
\(\frac{7}{60}+\frac{3}{40}+\frac{-11}{30}=\frac{280}{240}+\frac{180}{240}+\frac{-88}{240}=\frac{280+180+\left(-88\right)}{240}\frac{31}{20}\)
\(B)MSC:30\)
\(\frac{1}{2}+\frac{1}{3}+\frac{1}{5}=\frac{15}{30}+\frac{10}{30}+\frac{6}{30}=\frac{15+10+6}{30}=\frac{31}{30}\)
\(C)MSC:63\)
\(\frac{-4}{7}+\frac{8}{9}+\frac{-10}{21}=\frac{-252}{63}+\frac{56}{63}+\frac{-30}{63}=\frac{\left(-252\right)+56+\left(-30\right)}{63}=\frac{-226}{63}\)
k cho mình nha!