\(\frac{1}{9}.\frac{2}{145}-\frac{13}{3}:\frac{1}{145}+\frac{2}{145}=\frac{2}{145}\left(\frac{1}{9}+1\right)-\frac{13}{3}:\frac{1}{145}=\frac{2}{145}.\frac{10}{9}-\frac{1885}{3}=\frac{4}{216}-\frac{1885}{3}\)

\(=-\frac{33929}{54}\)

a,\(\frac{3}{2}\cdot\frac{7}{3}+\frac{4}{3}\cdot\frac{1}{2}\)=\(\frac{7}{2}+\frac{2}{3}\)=\(\frac{25}{6}\)

b,\(\frac{2}{145}\cdot\left(\frac{1}{9}-\frac{13}{3}+1\right)\)=\(\frac{2}{145}.-\frac{29}{9}=-\frac{2}{45}\)

c.\(\frac{15}{7}:\left(-\frac{31}{12}-\frac{1}{18}-\frac{20}{9}\right)\)=\(\frac{15}{7}:\left(-\frac{175}{36}\right)=-\frac{108}{245}\)

\(1\frac{1}{2}.2\frac{1}{3}+1\frac{1}{3}.\frac{1}{2}\)

\(=\frac{3}{2}.\frac{7}{3}+\frac{4}{3}.\frac{1}{2}\)

\(=\frac{7}{2}+\frac{2}{3}\)

\(=\frac{25}{6}\)

\(\frac{1}{9}.\frac{2}{145}-4\frac{1}{3}.\frac{2}{145}+\frac{2}{145}\)

\(=\frac{2}{1305}-\frac{13}{3}.\frac{2}{145}+\frac{2}{145}\)

\(=\frac{2}{1305}-\frac{26}{435}+\frac{2}{145}\)

\(=\frac{-2}{45}\)

\(\left(-2\frac{7}{12}\right):2\frac{1}{7}-\frac{1}{18}:2\frac{1}{7}+2\frac{2}{9}:2\frac{1}{7}\)

\(=\frac{-17}{12}:\frac{15}{7}-\frac{1}{18}:\frac{15}{7}+\frac{20}{9}:\frac{15}{7}\)

\(=\left(\frac{-17}{2}-\frac{1}{18}+\frac{20}{9}\right):\frac{15}{7}\)

\(=\frac{-19}{3}.\frac{7}{15}\)

\(=\frac{-133}{45}\)

học tốt

a,    1 1/2 . 2 1/3 + 1 1/3 . 1/2

       =77/2+11/6

       =121/3

xin lỗi nha

\(=\frac{2}{145}\left(\frac{1}{9}+1\right)-\frac{13}{3}.\frac{1}{145}\)

\(=\frac{2}{145}.\frac{10}{9}-\frac{13}{3}.\frac{1}{145}\)

\(=\frac{1}{145}+\frac{1}{145}.\frac{10}{9}-\frac{13}{3}.\frac{1}{145}\)

\(=\frac{1}{145}\left(\frac{10}{9}-\frac{13}{3}+1\right)\)

\(=\frac{1}{145}.-\frac{20}{9}\)

\(=-\frac{4}{261}\)

Mk bị nhầm chỗ 2. 145 thành 2/145 nhé. thank kiuf.

\(\frac{1}{9}.\frac{2}{145}-\frac{13}{3}.\frac{2}{245}+\frac{2}{145}\)

\(=\frac{2}{145}\left(\frac{1}{9}-\frac{13}{3}+1\right)\)

\(=\frac{2}{145}.\left(-\frac{29}{9}\right)\)

\(=-\frac{2}{45}\)

a) \(\frac{3}{2}.\frac{7}{2}+\frac{5}{3}.\frac{1}{2}=\frac{21}{2}+\frac{5}{6}=\frac{63}{6}+\frac{5}{6}=\frac{68}{6}=\frac{34}{3}\)

b) \(\frac{1}{9}.\frac{2}{145}-\frac{13}{3}.\frac{2}{145}+\frac{2}{145}=\frac{2}{145}\left(\frac{1}{9}-\frac{39}{9}+\frac{9}{9}\right)=\frac{2}{145}\left(-29\right)=-0.4\)

c) \(\left(-\frac{91}{12}\right):\frac{15}{7}-\frac{1}{18}:\frac{15}{7}+\frac{20}{9}:\frac{15}{7}=\frac{7}{15}\left(-\frac{91}{12}-\frac{1}{18}+\frac{20}{9}\right)=\frac{7}{15}\left(-\frac{65}{12}\right)=-\frac{91}{36}\)

1/ -2020 + (1543 + 2020)

\(=-2020+1543+2020\)

\(=-2020+2020+1543\)

\(=0+1543\)

\(=1543\)
2/ (245 – 97) – 245

\(=245-97-245\)

\(=245-245-97\)

\(=0-97\)

\(=-97\)
3/ (-145) – (118 – 145)

\(=-145-118+145\)

\(=-145+145-118\)

\(=0-118\)

\(=-118\)
4/ (-36 + 89) - (145 + 89 – 36)

\(=-36+89-145-89+36\)

\(=\left(-36+36\right)+\left(89-89\right)-145\)

\(=0+0-145\)

\(=-145\)

học tốt

1/ -2020+(1543+2020)

=-2020+1543+2020

=(-2020+2020)+1543

=0+1543=1543

2/ (245-97)-245

=245-97-245

=(245-245)-97

=0-97=-97

3/ -145-118+145

=(-145+145)-118

=0-118=-118

4/ -36+89-145-89+36

=(-36+36)+(89-89)-145

=0+0-145=-145

mik đang cần gấp

giúp mik với ☹

del

1)-7264+(1543+7264)=-7264+1543+7264=1543

2)(144-97)-144=144-97-144=-97

3)(-145)-(18-145)=-145-18+145=-18

4)111+(-11+27)=111-11+27=100+27=127

5)(27+514)-(486-73)=27+514-486-73=541-486-73=55-73=-18

6)(36+79)+(145-79-36)=36+79+145-79-36=145

7)10-[12-(-9-1)]=10-[12+9+1]=10-12-9-1=-12

8)(38-29+43)-(43+38)=38-29+43-43-38=-29

9)271-[(-43)+271-(-17)]=271-[-43+271+17]=271+43-271-17=43-17=26

10)-144-[29-(+144)-(+144)]=-144-[29-144-144]=-144-29+144+144=-29+144=115

c) \(\left(11+12+13+...+19\right).\left(6.8-48\right)=\left(11+12+13+...+19\right).\left(48-48\right)\)

                                                                                         \(=\left(11+12+13+...+19\right).0\)

                                                                                         \(=0\)

Hok "tuốt" nha^^

b) \(\left(500.9-250.18\right).\left(1+2+3+...+9\right)=\left(250.2.9-250.18\right).\left(1+2+...+9\right)\)

                                                                                             \(=\left(250.18-250.18\right).\left(1+2+3+...+9\right)\)

                                                                                             \(=0.\left(1+2+3+...+9\right)\)

                                                                                             \(=0\)

Hok tốt nha^^ (lần 2)