Bài 1: tính nhanh
a, \(\frac{6}{7}\)+\(\left(\frac{2}{11}-\frac{6}{7}\right)\)
b, \(\frac{15}{34}+\frac{7}{21}+\frac{9}{34}-1\frac{15}{17}+\frac{2}{3}\)
c, \(\frac{3}{7}.\frac{2}{9}+\frac{7}{9}.\frac{3}{7}\)
Bài dễ ai nhanh tay tui tick cho nè ^^
Tính nhanh:
a) \(2.\frac{3}{7}+\left(\frac{2}{9}-1\frac{3}{7}\right)-\frac{5}{3}:\frac{1}{9}\)
b) \(\frac{-11}{23}.\frac{6}{7}+\frac{8}{7}.\frac{-11}{23}-\frac{1}{23}\)
c )\(\left(\frac{377}{-231}-\frac{123}{89}+\frac{34}{791}\right).\left(\frac{1}{6}-\frac{1}{8}-\frac{1}{24}\right)\)
d) \(19\frac{5}{8}:\frac{7}{12}-15\frac{1}{4}:\frac{7}{12}\)
e) \(\frac{2}{5}.\frac{1}{3}-\frac{2}{15}:\frac{1}{5}+\frac{3}{5}.\frac{1}{3}\)
a: \(=\dfrac{17}{7}+\dfrac{2}{9}-\dfrac{10}{7}-\dfrac{5}{3}\cdot9=1+\dfrac{2}{9}-15=-14+\dfrac{2}{9}=-\dfrac{126}{9}+\dfrac{2}{9}=-\dfrac{124}{9}\)
b: \(=\dfrac{-11}{23}\left(\dfrac{6}{7}+\dfrac{8}{7}\right)-\dfrac{1}{23}=\dfrac{-22}{23}-\dfrac{1}{23}=-1\)
c: \(=\left(\dfrac{377}{-231}-\dfrac{123}{89}+\dfrac{34}{791}\right)\cdot\dfrac{4-3-1}{24}=0\)
d: \(=\dfrac{12}{7}\left(19+\dfrac{5}{8}-15-\dfrac{1}{4}\right)=\dfrac{12}{7}\cdot\dfrac{35}{8}=\dfrac{15}{2}\)
Tính giá trị biểu thức:
A = \(\frac{15}{34}+\frac{7}{21}+\frac{9}{34}-1\frac{15}{17}+\frac{2}{3}\) B = \(16\frac{2}{7}:\left(-\frac{3}{5}\right)-28\frac{2}{7}:\left(-\frac{3}{5}\right)\)
C = 25.\(\left(-\frac{1}{3}\right)^3+\frac{1}{5}-2.\left(-\frac{1}{2}\right)^2-\frac{1}{2}\)
a: \(A=\left(\dfrac{15}{34}+\dfrac{9}{34}-1-\dfrac{15}{17}\right)+\left(\dfrac{1}{3}+\dfrac{2}{3}\right)\)
\(=\left(\dfrac{12}{17}-1-\dfrac{15}{17}\right)+1\)
\(=\dfrac{-20}{17}+1=\dfrac{-3}{17}\)
b: \(B=\dfrac{-5}{3}\cdot16\dfrac{2}{7}-\dfrac{-5}{3}\cdot28\dfrac{2}{7}\)
\(=\dfrac{-5}{3}\left(16+\dfrac{2}{7}-28-\dfrac{2}{7}\right)=\dfrac{-5}{3}\cdot\left(-12\right)=20\)
c: \(C=25\cdot\dfrac{-1}{27}+\dfrac{1}{5}-2\cdot\dfrac{1}{4}-\dfrac{1}{2}\)
\(=\dfrac{-25}{27}+\dfrac{1}{5}-1\)
\(=\dfrac{-125+27-135}{135}=\dfrac{-233}{135}\)
A =\(\frac{15}{34}+\frac{7}{21}+\frac{9}{34}-1\frac{15}{17}+\frac{2}{3}\)
B = \(16\frac{2}{7}:\left(-\frac{3}{5}\right)-28\frac{2}{7}:\left(-\frac{3}{5}\right)\)
\(A=\frac{15}{34}+\frac{7}{21}+\frac{9}{34}-1\frac{15}{17}+\frac{2}{3}\)
\(=\frac{12}{17}+\frac{1}{3}-\frac{32}{17}+\frac{2}{3}\)
\(=-\frac{20}{17}+\frac{1}{3}+\frac{2}{3}\)
\(=-\frac{20}{17}+1\)
\(=-\frac{3}{17}\)
\(B=16\frac{2}{7}:\left(-\frac{3}{5}\right)-28\frac{2}{7}:\left(-\frac{3}{5}\right)\)
\(=\left(\frac{114}{7}-\frac{198}{7}\right):\left(-\frac{3}{5}\right)\)
\(=\left(-12\right):\left(-\frac{3}{5}\right)\)
\(=20\)
A\(=\frac{15}{34}+\frac{7}{21}+\frac{9}{34}-1\frac{15}{17}+\frac{2}{3}\)
\(=\left(\frac{15}{34}+\frac{9}{34}\right)+\left(\frac{7}{21}+\frac{2}{3}\right)-1\frac{15}{17}\)
\(=\left(\frac{14}{17}-\frac{15}{17}\right)+1-1\)
\(=-\frac{1}{17}\)
\(B=16\frac{2}{7}:\left(-\frac{3}{5}\right)-28\frac{2}{7}:\left(-\frac{3}{5}\right)\)
\(B=-\frac{3}{5}.\left(16\frac{2}{7}-28\frac{2}{7}\right)\)
\(B=-\frac{3}{5}.\left(-12\right)\)
\(B=\frac{36}{5}\)
Hoctot
A=\(\frac{15}{34}\)+ \(\frac{7}{21}\)+ \(\frac{9}{34}\)- 1\(\frac{15}{17}\)+ \(\frac{2}{3}\)
= ( \(\frac{15}{34}\)+ \(\frac{9}{34}\)) + ( \(\frac{7}{21}\)+ \(\frac{2}{3}\)) - \(\frac{32}{17}\)
= \(\frac{24}{34}\)+ ( \(\frac{7}{21}\)+ \(\frac{14}{21}\)) - \(\frac{32}{17}\)
=\(\frac{12}{17}\)+ \(\frac{21}{21}\)- \(\frac{32}{17}\)
= ( \(\frac{12}{17}\) - \(\frac{32}{17}\)) +1
=\(\frac{-20}{17}\)+ \(\frac{17}{17}\)
= \(\frac{-3}{17}\)
Tính giá trị biểu thức:
\(A=\frac{15}{34}+\frac{7}{21}+\frac{9}{34}-1\frac{15}{17}+\frac{2}{3}\) \(B=16\frac{2}{7}:\left(\frac{-3}{5}\right)-28\frac{2}{7}:\left(\frac{-3}{5}\right)\)
\(C=25.\left(\frac{-1}{3}\right)^3+\frac{1}{5}-2.\left(\frac{-1}{2}\right)^2-\frac{1}{2}\)
tính nhanh :
a) \(\frac{-3}{7}+\frac{15}{26}-\left(\frac{2}{13}-\frac{3}{7}\right)\)
b) \(2.\frac{3}{7}+\left(\frac{2}{9}-1\frac{3}{7}\right)-\frac{5}{3}:\frac{1}{9}\)
c) \(\frac{-11}{23}.\frac{6}{7}+\frac{8}{7}.\frac{-11}{23}-\frac{1}{23}\)
d) \(\left(\frac{377}{-231}-\frac{123}{89}+\frac{34}{791}\right).\left(\frac{1}{6}-\frac{1}{8}-\frac{1}{24}\right)\)
a. \(\frac{-3}{7}+\frac{15}{26}-\left(\frac{2}{13}-\frac{3}{7}\right)=\frac{-3}{7}+\frac{15}{26}-\frac{2}{13}+\frac{3}{7}=\frac{15}{13.2}-\frac{2}{13}=\frac{15}{13.2}-\frac{2.2}{13.2}=\frac{15-4}{26}=\frac{11}{26}\)
C. \(\frac{-11}{23}.\frac{6}{7}+\frac{8}{7}.\frac{-11}{23}-\frac{1}{23}=\frac{1}{23}.\left(-11.\frac{6}{7}-11.\frac{8}{7}-1\right)=\frac{1}{23}.\left(-22-1\right)=\frac{1}{23}.\left(-23\right)=-1\)
a.
\(-\frac{3}{7}+\frac{15}{26}-\left(\frac{2}{13}-\frac{3}{7}\right)\)
\(=-\frac{3}{7}+\frac{15}{26}-\frac{2}{13}+\frac{3}{7}\)
\(=\left(\frac{3}{7}-\frac{3}{7}\right)+\left(\frac{15}{26}-\frac{2}{13}\right)\)
\(=0+\left(\frac{15-4}{26}\right)\)
\(=\frac{11}{26}\)
c.
\(-\frac{11}{23}\times\frac{6}{7}+\frac{8}{7}\times\frac{-11}{23}-\frac{1}{23}\)
\(=-\frac{11}{23}\times\left(\frac{6}{7}+\frac{8}{7}\right)-\frac{1}{23}\)
\(=-\frac{11}{23}\times\frac{14}{7}\)
\(=-\frac{11}{23}\times2-\frac{1}{23}\)
\(=-\frac{22}{23}-\frac{1}{23}\)
\(=-\frac{23}{23}\)
\(=-1\)
d.
\(\left(\frac{377}{-231}-\frac{123}{89}+\frac{34}{791}\right)\times\left(\frac{1}{6}-\frac{1}{8}-\frac{1}{24}\right)\)
\(=\left(\frac{377}{-231}-\frac{123}{89}+\frac{34}{791}\right)\times\left(\frac{4-3-1}{24}\right)\)
\(=\left(\frac{377}{-231}-\frac{123}{89}+\frac{34}{791}\right)\times\frac{0}{24}\)
\(=0\)
Chúc bạn học tốt
Tính nhanh :
\(\frac{-3}{7}+\frac{15}{26}-\left(\frac{2}{13}-\frac{3}{7}\right)\)
\(2.\frac{3}{7}+\left(\frac{2}{9}-1\frac{3}{7}\right)-\frac{5}{3}:\frac{1}{9}\)
\(\frac{-11}{23}.\frac{6}{7}+\frac{8}{7}.\frac{-11}{23}-\frac{1}{23}\)
\(\left(\frac{377}{-231}-\frac{123}{89}+\frac{34}{791}\right).\left(\frac{1}{6}-\frac{1}{8}-\frac{1}{24}\right)\)
a) \(\frac{-3}{7}+\frac{15}{26}-\left(\frac{2}{13}-\frac{3}{7}\right)=\frac{-3}{7}+\frac{15}{26}-\frac{2}{13}+\frac{3}{7}=\left(\frac{-3}{7}+\frac{3}{7}\right)+\left(\frac{15}{26}-\frac{2}{13}\right)\)
\(=\frac{15-4}{26}=\frac{11}{26}\)
c) \(\frac{-11}{23}.\frac{6}{7}+\frac{8}{7}.\frac{-11}{23}-\frac{1}{23}=\frac{-11}{23}.\left(\frac{6}{7}+\frac{8}{7}\right)-\frac{1}{23}\)
\(=\frac{-11}{23}.2-\frac{1}{23}=\frac{-22-1}{23}=\frac{-23}{23}=-1\)
d) Đặt \(\frac{377}{-231}-\frac{123}{89}+\frac{34}{791}=A\)
Ta có: \(A.\left(\frac{1}{6}-\frac{1}{8}-\frac{1}{24}\right)=A.\left(\frac{4-3-1}{24}\right)=A.0=0\)
A=\(\frac{15}{34}+\frac{7}{21}+\frac{9}{34}-1\frac{15}{17}+\frac{2}{3}\)
B=\(16\frac{2}{7}:\left(-\frac{3}{5}\right)-28\frac{2}{7}:\left(-\frac{3}{5}\right)\)
C=\(25\cdot\left(-\frac{1}{3}\right)^3+\frac{1}{5}-2\cdot\left(-\frac{1}{2}\right)^2-\frac{1}{2}\)
D=\(\left(-2\right)^3\cdot\left(\frac{3}{4}-0,25\right):\left(2\frac{1}{4}-1\frac{1}{6}\right)\)
E=\(5\sqrt{16}-4\sqrt{9}+\sqrt{25}-0,3\sqrt{400}\)
F=\(\left(-\frac{3}{2}\right)^2+|-\frac{5}{6}|-1\frac{1}{2}:6\)
\(A=\frac{15}{34}+\frac{7}{21}+\frac{9}{34}-1\frac{15}{17}+\frac{2}{3}=\frac{15}{34}+\frac{7}{21}+\frac{9}{34}-\frac{64}{34}+\frac{14}{21}=\left(\frac{15}{34}+\frac{9}{34}-\frac{64}{34}\right)+\left(\frac{7}{21}+\frac{14}{21}\right)=\frac{30}{34}+\frac{21}{21}=\frac{15}{17}+1=\frac{32}{17}\)
Kiểm tra bài : Nhân, chia số hữu tỉ
Thực hiện phép tính :
(1) \(-\frac{3}{2}.\frac{7}{10}=\frac{-3.7}{2.10}=\frac{-21}{20}\)
(2) \(\frac{-5}{3}.\frac{6}{11}=\frac{-5.6}{3.11}=\frac{-30}{33}\)
(3) \(2\frac{1}{3}.\left(-1\frac{2}{3}\right)=\frac{7}{3}.\left(-\frac{5}{3}\right)=\frac{7.\left(-5\right)}{3.3}=-\frac{35}{9}\)
(4) \(\frac{9}{10}:\left(-\frac{15}{11}\right)=\frac{9}{10}.\left(\frac{-11}{15}\right)=\frac{9.\left(-11\right)}{10.15}=-\frac{99}{150}=-\frac{33}{50}\)
(5) \(\left(-1\right):\frac{3}{8}=\frac{\left(-1\right).8}{3}=-\frac{8}{3}\)
(6) \(\frac{1}{2}.\left(-\frac{5}{4}\right).\frac{8}{7}=\frac{1.\left(-5\right)}{2.4}.\frac{8}{7}=-\frac{5}{8}.\frac{8}{7}=-\frac{5.8}{8.7}=-\frac{5}{7}\)
(7) \(\frac{-9}{2}.\frac{2}{18}.\frac{1}{7}=\left(-\frac{9}{2}.\frac{2}{18}\right).\frac{1}{7}=\left(-\frac{9.2}{2.18}\right).\frac{1}{7}=-\frac{18}{36}.\frac{1}{7}=-\frac{18.1}{36.7}=-\frac{1}{14}\)
(8) \(\left(\frac{9}{2}-\frac{1}{3}\right).\frac{6}{17}=\left(\frac{27}{6}-\frac{2}{6}\right).\frac{6}{17}=\frac{27-2}{6}.\frac{6}{17}=\frac{25}{6}.\frac{6}{17}=\frac{25.6}{6.17}=\frac{25}{17}\)
(9) \(\left(-\frac{12}{13}:\frac{36}{39}\right).\frac{3}{5}=\left(-\frac{12}{13}.\frac{39}{36}\right).\frac{3}{5}=\left(\frac{-12.39}{13.36}\right).\frac{3}{5}=-\frac{1.3}{5}=-\frac{3}{5}\)
(10) \(\left(-\frac{3}{7}+\frac{7}{9}\right):\frac{4}{7}+\left(-\frac{4}{7}+\frac{2}{9}\right):\frac{4}{7}=\left(\left(-\frac{3}{7}+\frac{7}{9}\right)+\left(-\frac{4}{7}+\frac{2}{9}\right)\right):\frac{4}{7}\)
\(=\left(\left(-\frac{27}{63}+\frac{49}{63}\right)+\left(-\frac{36}{63}+\frac{14}{63}\right)\right):\frac{4}{7}=\left(\left(-\frac{27+49}{63}\right)+\left(\frac{-36+14}{63}\right)\right):\frac{4}{7}\)
\(=\left(\left(\frac{22}{63}\right)+\left(-\frac{22}{63}\right)\right):\frac{4}{7}\)
\(=\frac{22+\left(-22\right)}{63}:\frac{4}{7}=\frac{0}{63}:\frac{4}{7}=0\)
Mình đăng các bài toán này lên thứ nhất là để kiểm tra năng lực thứ hai các bạn có thể xem đây và rút ra lời giải cho các bài khác và nếu mình sai chỗ nào các bạn chỉ mình sẽ chỉnh
B1: Thực hiện phép tính :
a, \(11\frac{3}{4}-(6\frac{5}{6}-4\frac{1}{2})+1\frac{2}{3}\)
b, \(2\frac{17}{20}-1\frac{11}{5}+6\frac{9}{20}:3\)
c, \(4\frac{3}{7}:\left(\frac{7}{5}.4\frac{3}{7}\right)\)
d, \(\left(3\frac{2}{9}.\frac{15}{23}.1\frac{7}{29}\right):\frac{5}{23}\)
B2: Thực hiện phép tính:
\(a,11\frac{3}{4}-(6\frac{5}{6}4\frac{1}{2}+1\frac{2}{3})\\ b,\left(5\frac{7}{8}-2\frac{1}{4}-0,5\right):\frac{23}{26}\)
\(c,\left(17\frac{13}{15}-3\frac{3}{7}\right)-\left(2\frac{12}{15}-4\right)\\ d,2\frac{2}{3}.\frac{-4}{5}.0,375-\left(-10\right).\frac{-15}{24}\)