Question

Câu 3: Thực hiện phép tính:

a) \(\left( \frac{105}{31} - \frac{31}{202} + \frac{104}{91} \right) \left( \frac{1}{2} - \frac{1}{3} - \frac{1}{6} \right)\)

b) \(\left( \frac{2022}{71} - \frac{371}{20} + \frac{10}{93} \right) \left( \frac{1}{4} - \frac{1}{5} - \frac{1}{20} \right)\)

Câu 4: Thực hiện phép tính:

a) \(\frac{6}{7} \cdot \left( \frac{2}{5} - \frac{6}{7} \right)\)

b) \(\frac{6}{7} + \frac{5}{7} \cdot \frac{5}{8} - \frac{8}{9}\)

Câu 5: Thực hiện phép tính:

a) \(\frac{6}{7} + \frac{5}{8} - \frac{1}{5} - \frac{3}{16}\)

b) \(-\frac{1}{6} + \frac{2}{3} - \frac{3}{4} + \frac{4}{5}\)

Answer 1

3a) 

\(\left(\dfrac{105}{31}-\dfrac{31}{202}+\dfrac{104}{91}\right)\cdot\left(\dfrac{1}{2}-\dfrac{1}{3}-\dfrac{1}{6}\right)\\ =\left(\dfrac{105}{31}-\dfrac{31}{202}+\dfrac{104}{91}\right)\cdot\left(\dfrac{3}{6}-\dfrac{2}{6}-\dfrac{1}{6}\right)\\ =\left(\dfrac{105}{31}-\dfrac{31}{202}+\dfrac{104}{91}\right)\cdot0=0\)

\(b.\left(\dfrac{2022}{71}-\dfrac{371}{20}+\dfrac{10}{93}\right)\cdot\left(\dfrac{1}{4}-\dfrac{1}{5}-\dfrac{1}{20}\right)\\ =\left(\dfrac{2022}{71}-\dfrac{371}{20}+\dfrac{10}{93}\right)\cdot\left(\dfrac{5}{20}-\dfrac{4}{20}-\dfrac{1}{20}\right)\\ =\left(\dfrac{2022}{71}-\dfrac{371}{20}+\dfrac{10}{93}\right)\cdot0=0\)

Answer 2

Câu `3`

`a, (105/31 - 31/202 + 104/91)(1/2 - 1/3 - 1/6)`

`= (105/31 - 31/202 + 104/91)(3/6 - 2/6 - 1/6)`

`= (105/31 - 31/202 + 104/91) . 0`

`= 0`

`b, (2022/71 - 371/20 + 10/93)(1/4 - 1/5 - 1/20)`

`= (2022/71 - 371/20 + 10/93)(5/20- 4/20 - 1/20)`

`= (2022/71 - 371/20 + 10/93) . 0`

`=0`

Answer 3

bài 4

\(a.\dfrac{6}{7}\cdot\left(\dfrac{2}{5}-\dfrac{6}{7}\right) =\dfrac{6}{7}\cdot\left(-\dfrac{16}{35}\right)=-\dfrac{96}{245}\\ b.\dfrac{6}{7}+\dfrac{5}{7}\cdot\dfrac{5}{8}-\dfrac{8}{9}\\ =\dfrac{6}{7}+\dfrac{25}{56}-\dfrac{8}{9}=\dfrac{209}{504}\)

Answer 4

bài 4:

\(a.\dfrac{6}{7}:\left(\dfrac{2}{5}\cdot\dfrac{6}{7}\right)=\dfrac{6}{7}:\dfrac{12}{35}\\ =\dfrac{6}{7}\cdot\dfrac{35}{12}=\dfrac{6}{7}\cdot\dfrac{5\cdot7}{6\cdot2}=\dfrac{5}{2}\\ b.\dfrac{6}{7}+\dfrac{5}{7}:5-\dfrac{8}{9}=\dfrac{6}{7}+\dfrac{5}{7}\cdot\dfrac{1}{5}-\dfrac{8}{9}\\ =\dfrac{6}{7}+\dfrac{1}{7}-\dfrac{8}{9}=\dfrac{7}{7}-\dfrac{8}{9}=1-\dfrac{8}{9}=\dfrac{1}{9}\)

Answer 5

bài 5:

\(a.\dfrac{6}{7}+\dfrac{5}{8}\cdot\dfrac{1}{5}-\dfrac{3}{16}\cdot4=\dfrac{6}{7}+\dfrac{1}{8}-\dfrac{3}{4}\\ =\dfrac{48}{56}+\dfrac{7}{56}-\dfrac{42}{56}=\dfrac{13}{56}\\ b.\dfrac{-1}{6}+\dfrac{2}{3}\cdot\dfrac{-3}{4}+\dfrac{4}{5}=-\dfrac{1}{6}+\dfrac{-1}{2}+\dfrac{4}{5}\\ =\dfrac{-5}{30}-\dfrac{15}{30}+\dfrac{24}{30}=\dfrac{4}{30}=\dfrac{2}{15}\)