22 câu hỏi trắc nghiệm thuộc Giải SBT Toán 7 Bài 4. Quy tắc dấu ngoặc và quy tắc chuyển vế có đáp án

Bỏ ngoặc rồi tính.

a) $(\frac{- 3}{8}) + (\frac{7}{9} - \frac{5}{8})$

a) $(\frac{- 3}{8}) + (\frac{7}{9} - \frac{5}{8}) = (\frac{- 3}{8}) + \frac{7}{9} - \frac{5}{8}$

$= (\frac{- 3}{8}) - \frac{5}{8} + \frac{7}{9} = - 1 + \frac{7}{9}$

$= \frac{- 9}{9} + \frac{7}{9} = \frac{- 2}{9}$

Câu 2:

22/07/2024

Tính:

[(\frac{- 7}{8}) : \frac{21}{16}] - \frac{5}{3} . (\frac{1}{3} - \frac{7}{10})

b) $[(\frac{- 7}{8}) : \frac{21}{16}] - \frac{5}{3} . (\frac{1}{3} - \frac{7}{10})$

$= [(\frac{- 7}{8}) . \frac{16}{21}] - \frac{5}{3} . (\frac{10}{30} - \frac{21}{30})$

$= \frac{(- 7) . 16}{8 . 21} - \frac{5}{3} . (\frac{- 11}{30})$

$= - \frac{7 . 8 . 2}{8 . 7 . 3} + \frac{5 . 11}{3 . 5 . 6}$

$= \frac{- 2}{3} + \frac{11}{18} = \frac{- 1}{18}$

Câu 3:

Tính:

{[(\frac{- 2}{3}) + \frac{3}{4}]}^{2} . \frac{12}{5} - \frac{1}{5}

c) ${[(\frac{- 2}{3}) + \frac{3}{4}]}^{2} . \frac{12}{5} - \frac{1}{5}$

$= {[(\frac{- 8}{12}) + \frac{9}{12}]}^{2} . \frac{12}{5} - \frac{1}{5}$

$= {(\frac{1}{12})}^{2} . \frac{12}{5} - \frac{1}{5}$

$= \frac{1}{12^{2}} . \frac{12}{5} - \frac{1}{5}$

$= \frac{1}{60} - \frac{1}{5} = \frac{- 11}{60}$

Câu 4:

22/07/2024

Tính:

a) $(- 0, 5) - (- 1 + \frac{2}{3}) : 1, 5 + (\frac{- 1}{4})$

a) $(- 0, 5) - (- 1 + \frac{2}{3}) : 1, 5 + (\frac{- 1}{4})$

$= (\frac{- 1}{2}) - (\frac{- 3}{3} + \frac{2}{3}) : \frac{3}{2} + (\frac{- 1}{4})$

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

$= (\frac{- 1}{2}) + \frac{2}{9} + (\frac{- 1}{4})$

$= (\frac{- 18}{36}) + \frac{8}{36} + (\frac{- 9}{36}) = \frac{- 19}{36}$

Câu 5:

Bỏ ngoặc rồi tính.

\frac{4}{9} - (\frac{3}{7} + \frac{2}{9})

;

b) $\frac{4}{9} - (\frac{3}{7} + \frac{2}{9}) = \frac{4}{9} - \frac{3}{7} - \frac{2}{9}$

$= \frac{4}{9} - \frac{2}{9} - \frac{3}{7} = \frac{2}{9} - \frac{3}{7}$

$= \frac{14}{63} - \frac{27}{63} = \frac{- 13}{63}$

Câu 6:

Bỏ ngoặc rồi tính.

c) $[(\frac{- 2}{5}) + \frac{1}{3}] - (\frac{3}{5} - \frac{1}{4})$ ;

c) $[(\frac{- 2}{5}) + \frac{1}{3}] - (\frac{3}{5} - \frac{1}{4}) = (\frac{- 2}{5}) + \frac{1}{3} - \frac{3}{5} + \frac{1}{4}$

$= (\frac{- 2}{5}) - \frac{3}{5} + \frac{1}{3} + \frac{1}{4} = (- 1) + \frac{1}{3} + \frac{1}{4}$

$= (\frac{- 12}{12}) + \frac{4}{12} + \frac{3}{12} = \frac{- 5}{12}$

Câu 7:

Bỏ ngoặc rồi tính.

(1 \frac{1}{2} - \frac{3}{4}) - (0, 25 + \frac{1}{2})

d) $(1 \frac{1}{2} - \frac{3}{4}) - (0, 25 + \frac{1}{2}) = (\frac{3}{2} - \frac{3}{4}) - (\frac{1}{4} + \frac{1}{2})$

$= (\frac{3}{2} - \frac{3}{4}) - (\frac{1}{4} + \frac{1}{2})$

$= (\frac{3}{2} - \frac{1}{2}) - (\frac{3}{4} + \frac{1}{4})$

= 1 – 1 = 0.

Câu 8:

Cho biểu thức:

$A = (8 - \frac{2}{3} + \frac{1}{2}) - (5 - \frac{7}{3} - \frac{3}{2}) - (\frac{5}{3} + \frac{5}{2} + 4)$

Hãy tính giá trị của A theo hai cách:

a) Tính giá trị của từng biểu thức trong ngoặc trước.

a) $A = (8 - \frac{2}{3} + \frac{1}{2}) - (5 - \frac{7}{3} - \frac{3}{2}) - (\frac{5}{3} + \frac{5}{2} + 4)$

$= (\frac{48}{6} - \frac{4}{6} + \frac{3}{6}) - (\frac{30}{6} - \frac{14}{6} - \frac{9}{6}) - (\frac{10}{6} + \frac{15}{6} + \frac{24}{6})$

$= \frac{47}{6} - \frac{7}{6} - \frac{49}{6} = \frac{- 9}{6} = \frac{- 3}{2}$

Câu 9:

b) Bỏ dấu ngoặc rồi nhóm các số hạng thích hợp.

Cho biểu thức:

$A = (8 - \frac{2}{3} + \frac{1}{2}) - (5 - \frac{7}{3} - \frac{3}{2}) - (\frac{5}{3} + \frac{5}{2} + 4)$

Hãy tính giá trị của A theo hai cách:

b) $A = (8 - \frac{2}{3} + \frac{1}{2}) - (5 - \frac{7}{3} - \frac{3}{2}) - (\frac{5}{3} + \frac{5}{2} + 4)$

$= 8 - \frac{2}{3} + \frac{1}{2} - 5 + \frac{7}{3} + \frac{3}{2} - \frac{5}{3} - \frac{5}{2} - 4$

$= (8 - 5 - 4) + (\frac{7}{3} - \frac{2}{3} - \frac{5}{3}) + (\frac{1}{2} + \frac{3}{2} - \frac{5}{2})$

$= (- 1) + 0 - \frac{1}{2} = \frac{- 3}{2}$

Câu 10:

Tính:

{(\frac{1}{25} - 0, 4)}^{2} : \frac{9}{125} - [(1 \frac{1}{3} - \frac{2}{5}) . \frac{3}{7}]

d) ${(\frac{1}{25} - 0, 4)}^{2} : \frac{9}{125} - [(1 \frac{1}{3} - \frac{2}{5}) . \frac{3}{7}]$

$= {(\frac{1}{25} - \frac{2}{5})}^{2} . \frac{125}{9} - [(\frac{4}{3} - \frac{2}{5}) . \frac{3}{7}]$

$= {(\frac{- 9}{25})}^{2} . \frac{125}{9} - [\frac{14}{15} . \frac{3}{7}]$

$= \frac{9^{2}}{25^{2}} . \frac{125}{9} - \frac{2}{5} = \frac{{(3^{2})}^{2}}{{(5^{2})}^{2}} . \frac{5^{3}}{3^{2}} - \frac{2}{5}$

$= \frac{3^{4}}{5^{4}} . \frac{5^{3}}{3^{2}} - \frac{2}{5} = \frac{3^{2}}{5} - \frac{2}{5}$

$= \frac{9}{5} - \frac{2}{5} = \frac{7}{5}$

Câu 11:

23/07/2024

Tìm x, biết:

a) $x + \frac{3}{7} = \frac{2}{5}$

a) $x + \frac{3}{7} = \frac{2}{5}$

$x = \frac{2}{5} - \frac{3}{7}$

$x = \frac{14}{35} - \frac{15}{35}$

$x = \frac{- 1}{35}$

Câu 12:

Tìm x, biết:

b) $\frac{5}{9} - \frac{1}{3} x = \frac{2}{3}$

b) $\frac{3}{2} - x = \frac{4}{5}$

$x = \frac{3}{2} - \frac{4}{5}$

$x = \frac{15}{10} - \frac{8}{10}$

$x = \frac{7}{10}$

Câu 13:

\frac{5}{9} - \frac{1}{3} x = \frac{2}{3}

c) $\frac{5}{9} - \frac{1}{3} x = \frac{2}{3}$

$\frac{1}{3} x = \frac{5}{9} - \frac{2}{3}$

$\frac{1}{3} x = \frac{- 1}{9}$

$x = (\frac{- 1}{9}) : \frac{1}{3}$

$x = \frac{- 1}{3}$

Câu 14:

\frac{3}{5} x - 1 \frac{1}{5} = \frac{- 3}{14} : \frac{5}{7}

d) $\frac{3}{5} x - 1 \frac{1}{5} = \frac{- 3}{14} : \frac{5}{7}$

$\frac{3}{55} x - \frac{6}{5} = \frac{- 3}{10}$

$\frac{3}{5} x = \frac{- 3}{10} + \frac{6}{5}$

$\frac{3}{5} x = \frac{9}{10}$

$x = \frac{3}{2}$

Câu 15:

Tìm x, biết:

a) $\frac{3}{4} + \frac{1}{9} : x = 0, 5$

a) $\frac{3}{4} + \frac{1}{9} : x = 0, 5$

$\frac{1}{9} : x = \frac{1}{2} - \frac{3}{4}$

$\frac{1}{9} : x = \frac{- 1}{4}$

$x = \frac{1}{9} : (\frac{- 1}{4})$

$x = \frac{1}{9} . (- 4)$

$x = \frac{- 4}{9}$

Câu 16:

23/07/2024

\frac{3}{4} - (x - \frac{2}{3}) = 1 \frac{1}{3}

b) $\frac{3}{4} - (x - \frac{2}{3}) = 1 \frac{1}{3}$

$x - \frac{2}{3} = \frac{3}{4} - \frac{4}{3}$

$x - \frac{2}{3} = \frac{- 7}{12}$

$x = \frac{- 7}{12} + \frac{2}{3}$

$x = \frac{1}{12}$

Câu 17:

23/07/2024

c) $(\frac{5}{7} - x) . \frac{11}{15} = \frac{- 22}{45}$

c) $(\frac{5}{7} - x) . \frac{11}{15} = \frac{- 22}{45}$

$\frac{5}{7} - x = (\frac{- 22}{45}) : \frac{11}{15}$

$\frac{5}{7} - x = (\frac{- 22}{45}) . \frac{15}{11}$

$\frac{5}{7} - x = \frac{- 2}{3}$

$x = \frac{5}{7} - (\frac{- 2}{3})$

$x = \frac{29}{21}$

Câu 18:

(2, 5 x - \frac{4}{7}) : \frac{8}{21} = - 1, 5

d) $(2, 5 x - \frac{4}{7}) : \frac{8}{21} = - 1, 5$

$(\frac{5}{2} x - \frac{4}{7}) : \frac{8}{21} = \frac{- 3}{2}$

$\frac{5}{2} x - \frac{4}{7} = (\frac{- 3}{2}) . \frac{8}{21}$

$\frac{5}{2} x - \frac{4}{7} = \frac{- 4}{7}$

$\frac{5}{2} x = (\frac{- 4}{7}) + \frac{4}{7}$

$\frac{5}{2} x = 0$

x=0

Câu 19:

Tính nhanh:

a) $\frac{12}{23} . \frac{7}{13} + \frac{11}{23} . \frac{7}{13}$

a) $\frac{12}{23} . \frac{7}{13} + \frac{11}{23} . \frac{7}{13}$

$= \frac{7}{13} . (\frac{12}{23} + \frac{11}{23})$

$= \frac{7}{13} . 1 = \frac{7}{13}$

Câu 20:

22/07/2024

Tính nhanh:

\frac{4}{9} . \frac{23}{11} - \frac{1}{11} . \frac{4}{9} + \frac{4}{9}

b) $\frac{4}{9} . \frac{23}{11} - \frac{1}{11} . \frac{4}{9} + \frac{4}{9}$

$= \frac{4}{9} . (\frac{23}{11} - \frac{1}{11} + 1)$

$= \frac{4}{9} . (2 + 1) = \frac{4}{9} .3 = \frac{4}{3}$

Câu 21:

20/07/2024

Tính nhanh:

[(- \frac{5}{7}) + \frac{3}{5}] : \frac{2020}{2021} + (\frac{2}{5} - \frac{2}{7}) : \frac{2020}{2021}

c) $[(- \frac{5}{7}) + \frac{3}{5}] : \frac{2020}{2021} + (\frac{2}{5} - \frac{2}{7}) : \frac{2020}{2021}$

$= [(- \frac{5}{7}) + \frac{3}{5}] . \frac{2021}{2020} + (\frac{2}{5} - \frac{2}{7}) . \frac{2021}{2020}$

$= [(- \frac{5}{7}) + \frac{3}{5} + \frac{2}{5} - \frac{2}{7}] . \frac{2021}{2020}$

$= (1 - 1) . \frac{2021}{2020} = 0. \frac{2021}{2020} = 0$

Câu 22:

Tính nhanh

\frac{3}{8} : (\frac{7}{22} - \frac{2}{11}) + \frac{3}{8} : (\frac{2}{5} - \frac{1}{10})