Bài 3:
a: \(A=\left\lbrace\left\lbrack\left(1-\frac23\right)^2:\frac29\right\rbrack-1\right\rbrace\cdot\frac45\)
\(=\left\lbrack\left(\frac13\right)^2:\frac29-1\right\rbrack\cdot\frac45\)
\(=\left(\frac19\cdot\frac92-1\right)\cdot\frac45=\left(\frac12-1\right)\cdot\frac45=\frac{-1}{2}\cdot\frac45=-\frac25\)
b: \(B=\left\lbrack\left(\frac25+1\right):\frac23\right\rbrack\left(\frac34-\frac18\right)^2\)
\(=\left\lbrack\left(\frac25+\frac55\right)\cdot\frac32\right\rbrack\cdot\left(\frac68-\frac18\right)^2\)
\(=\frac75\cdot\frac32\cdot\left(\frac58\right)^2=\frac{21}{10}\cdot\frac{25}{64}=\frac{25}{10}\cdot\frac{21}{64}=\frac52\cdot\frac{21}{64}=\frac{105}{128}\)
Bài 2:
1: \(\frac38\cdot19\frac13-\frac38\cdot33\frac13\)
\(=\frac38\left(19+\frac13-33-\frac13\right)\)
\(=-14\cdot\frac38=-\frac{42}{8}=-\frac{21}{4}\)
2: \(\left(\frac{5}{34}+\frac13\right)-\left(-\frac{29}{34}+\frac43\right)\)
\(=\frac{5}{34}+\frac13+\frac{29}{34}-\frac43\)
\(=\frac{34}{34}-\frac33=1-1=0\)
3: \(\left(-\frac59\right)\cdot\frac{3}{11}+\left(-\frac{8}{18}\right)\cdot\frac{3}{11}\)
\(=\frac{3}{11}\left(-\frac59-\frac49\right)\)
\(=\frac{3}{11}\cdot\frac{-9}{9}=-\frac{3}{11}\)
4: \(\left(\frac73+\frac{11}{25}\right)-\left(\frac13-\frac{14}{25}\right)\)
\(=\frac73+\frac{11}{25}-\frac13+\frac{14}{25}\)
\(=\frac63+\frac{25}{25}=2+1=3\)
5: \(-\left(\frac95+\frac{16}{3}\right)+\left(-2025+\frac95\right)-\frac23\)
\(=-\frac95-\frac{16}{3}-2025+\frac95-\frac23\)
\(=-2025-\frac{18}{3}=-2025-6=-2031\)
6: \(\left(\frac27-\frac94\right)-\left(-\frac37+\frac54\right)-\left(\frac24-\frac97\right)\)
\(=\frac27-\frac94+\frac37-\frac54-\frac24+\frac97=\left(\frac27+\frac37+\frac97\right)-\left(\frac94+\frac54+\frac24\right)\)
\(=\frac{14}{7}-\frac{16}{4}=2-4=-2\)
7: \(\left(51,3+12,8\right)-\left(51,3-17,2\right)\)
=51,3+12,8-51,3+17,2
=12,8+17,2
=30
8: \(2,5\cdot\left(-4,68\right)+2,5\cdot\left(-5,32\right)\)
\(=2,5\left(-4,68-5,32\right)\)
\(=2,5\cdot\left(-10\right)=-25\)
Bài 1:
a: \(\frac{25}{12}+\frac{-4}{12}=\frac{25-4}{12}=\frac{21}{12}=\frac74\)
b: \(-\frac{7}{15}-\frac{-2}{15}=-\frac{7}{15}+\frac{2}{15}=\frac{-7+2}{15}=-\frac{5}{15}=-\frac13\)
c: \(\frac38+\frac{-14}{6}=\frac38-\frac73=\frac{9}{24}-\frac{56}{24}=\frac{-47}{24}\)
d: \(\frac{5}{12}-\frac{13}{15}=\frac{25}{60}-\frac{52}{60}=\frac{25-52}{60}=\frac{-27}{60}=-\frac{9}{20}\)
e: \(\frac23+\frac{-10}{6}+\frac{-4}{3}=\frac23-\frac53-\frac43=\frac{2-5-4}{3}=\frac{-7}{3}\)
f: \(\frac73-\left(-\frac14-\frac{5}{12}\right)=\frac73+\frac14+\frac{5}{12}\)
\(=\frac{28}{12}+\frac{3}{12}+\frac{5}{12}=\frac{28+3+5}{12}=\frac{36}{12}=3\)
g: \(-\frac43:\frac{13}{9}=-\frac43\cdot\frac{9}{13}=\frac{-4\cdot3}{13}=-\frac{12}{13}\)
h: \(\left(\frac12\right)^3\cdot4+\frac34=\frac18\cdot4+\frac34=\frac34+\frac12=\frac34+\frac24=\frac54\)
