Câu hỏi của Bùi Ngọc Hân

Question

undefined Giúp mik 2 bài với nhá

Nguyễn Lê Phước Thịnh · Accepted Answer

Câu 1:

a: $\frac{-1}{8}+\frac58+\frac38=\frac{-1+5+3}{8}=\frac78$

b: $\frac73-\frac53-\frac83=\frac{7-5-8}{3}=\frac{-6}{3}=-2$

c: $-\frac32+\frac56+\frac13$

$=-\frac96+\frac56+\frac26$

$=\frac{-9+7}{6}=-\frac26=-\frac13$

d: $-\frac34-\frac12+\frac58=-\frac68+\frac58-\frac48=\frac{-6+5-4}{8}=\frac{-1-4}{8}=-\frac58$

e: $-\frac35\cdot\frac74+\frac{3}{10}=\frac{-21}{20}+\frac{6}{20}=\frac{-15}{20}=-\frac34$

f: $-\frac94-\frac45:\frac43$

$=-\frac94-\frac35=\frac{-45-12}{20}=-\frac{57}{20}$

Câu 2:

a: $-\frac14+\frac35-\frac34+\frac25+\frac23$

$=\left(-\frac14-\frac34\right)+\left(\frac35+\frac25\right)+\frac23$

$=-1+1+\frac23=\frac23$

b: $\frac73-\frac38+\frac23-\frac58+1$

$=\left(\frac73+\frac23\right)-\left(\frac38+\frac58\right)+1$

=3-1+1

=3

c: $-\frac56\cdot\frac23+\frac{-5}{6}\cdot\frac13=-\frac56\left(\frac23+\frac13\right)=-\frac56$

d: $\frac78\cdot\frac35+\frac78\cdot\frac25-\frac78$

$=\frac78\left(\frac35+\frac25\right)-\frac78$

$=\frac78-\frac78=0$

Câu trả lời: