Tính giá trị của các biểu thức sau : a)$\left(7 3\dfrac{1}{4}-\dfrac{3}{5}\right)$ (0,4 - 5) - $\left(4\dfrac{1}{4}-1\right)$ b)$\dfrac{2}{3}$ - \(\left[\left(-\dfrac{7}{4}\right)-\left(\dfrac...

Tính bằng cách hợp lí giá trị của biểu thức. A = $\left(3-\dfrac{1}{4} +\dfrac{3}{2}\right)$- $\left(5+\dfrac{1}{3}-\dfrac{5}{6}\right)$-$\left(6-\dfrac{7}{4}+\dfrac{3}{2}\right)$ B...

1

TT

Thư Thư

21 tháng 6 2023

$a,\left(7+3\dfrac{1}{4}-\dfrac{3}{5}\right)+\left(0,4-5\right)-\left(4\dfrac{1}{4}-1\right)$

$=\left(7+\dfrac{13}{4}-\dfrac{3}{5}\right)-\dfrac{23}{5}-\left(\dfrac{17}{4}-1\right)$

$=7+\dfrac{13}{4}-\dfrac{3}{5}-\dfrac{23}{5}-\dfrac{17}{4}+1$

$=\left(7+1\right)+\left(\dfrac{13}{4}-\dfrac{17}{4}\right)-\left(\dfrac{3}{5}+\dfrac{23}{5}\right)$

$=8-\dfrac{4}{4}-\dfrac{26}{5}$

$=7-\dfrac{26}{5}$

$=\dfrac{9}{5}$

$b,\dfrac{2}{3}-\left[\left(-\dfrac{7}{4}\right)-\left(\dfrac{1}{2}+\dfrac{3}{8}\right)\right]$

$=\dfrac{2}{3}-\left(-\dfrac{7}{4}-\dfrac{1}{2}-\dfrac{3}{8}\right)$

$=\dfrac{2}{3}-\left(-\dfrac{14}{8}-\dfrac{4}{8}-\dfrac{3}{8}\right)$

$=\dfrac{2}{3}-\left(-\dfrac{21}{8}\right)$

$=\dfrac{2}{3}+\dfrac{21}{8}$

$=\dfrac{79}{24}$

$c,\left(9-\dfrac{1}{2}-\dfrac{3}{4}\right):\left(7-\dfrac{1}{4}-\dfrac{5}{8}\right)$

$=\left(\dfrac{36}{4}-\dfrac{2}{4}-\dfrac{3}{4}\right):\left(\dfrac{56}{8}-\dfrac{2}{8}-\dfrac{5}{8}\right)$

$=\dfrac{31}{4}:\dfrac{49}{8}$

$=\dfrac{62}{49}$

$d,3-\dfrac{1-\dfrac{1}{7}}{1+\dfrac{1}{7}}=3-\dfrac{\dfrac{7}{7}-\dfrac{1}{7}}{\dfrac{7}{7}+\dfrac{1}{7}}=3-\left(\dfrac{6}{7}:\dfrac{8}{7}\right)=3-\dfrac{3}{4}=\dfrac{9}{4}$

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HP

Hồng Phong Đoàn

19 tháng 10 2023

2

NM

Nguyễn Minh Dương

VIP

19 tháng 10 2023

$A=\left(3-\dfrac{1}{4}+\dfrac{3}{2}\right)-\left(5+\dfrac{1}{3}-\dfrac{5}{6}\right)-\left(6-\dfrac{7}{4}+\dfrac{2}{3}\right)\\ \Rightarrow A=3-\dfrac{1}{4}+\dfrac{3}{2}-5-\dfrac{1}{3}+\dfrac{5}{6}-6+\dfrac{7}{4}-\dfrac{2}{3}\\ \Rightarrow A=\left(3-5-6\right)-\left(\dfrac{1}{4}+\dfrac{7}{4}\right)+\left(\dfrac{3}{2}+\dfrac{5}{6}-\dfrac{2}{3}\right)\\ \Rightarrow A=-8-\dfrac{3}{2}+\dfrac{5}{3}\\ =-\dfrac{47}{6}.\\ B=0,5+\dfrac{1}{3}+0,4+\dfrac{5}{7}+\dfrac{1}{6}-\dfrac{4}{35}+\dfrac{1}{41}$

$\Rightarrow B=\left(0,5+0,4\right)+\left(\dfrac{1}{3}+\dfrac{1}{6}\right)+\left(\dfrac{5}{7}-\dfrac{4}{35}\right)+\dfrac{1}{41}\\ \Rightarrow B=\dfrac{9}{10}+\dfrac{1}{2}+\dfrac{3}{5}+\dfrac{1}{41}\\ \Rightarrow B=2+\dfrac{1}{41}\\ \Rightarrow B=\dfrac{83}{41}.$

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NP

Ngô Phúc Nhã Uyên

VIP

29 tháng 10 2023

-_-

LG

Lưu Gia Lợi

20 tháng 5 2022

Tính giá trị của biểu...

Tính giá trị của biểu thức: a) (-7,05 - $\dfrac{1}{4}$) : (-5) + $\dfrac{1}{15}$ - $\left(-\dfrac{1}{5}\right)$ : (-3) b) $\left(\dfrac{3}{25}-1,12\right)$ : $\dfrac{3}{7}$ :...

#Toán lớp 6

1

NH

Nguyễn Hà Tuấn Hưng 7A14

20 tháng 5 2022

A= 4/7.

Biết có cái

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LP

Lê Phương Linh

20 tháng 11 2023

tính giá trị biểu thức...

1

BA

Bùi Anh Đức

21 tháng 11 2023

a) = ($-\dfrac{141}{20}$- $\dfrac{1}{4}$) : (-5) + $\dfrac{1}{15}$ - $\dfrac{1}{15}$

= $-\dfrac{73}{10}$ : - 5

= $\dfrac{73}{50}$

b) = $\left(\dfrac{3}{25}-\dfrac{28}{25}\right)$. $\dfrac{7}{3}$ : $\left(\dfrac{7}{2}-\dfrac{11}{3}.14\right)$

= $-\dfrac{7}{3}$ . $-\dfrac{6}{287}$

= $\dfrac{2}{41}$

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T

títtt

7 tháng 1

#Toán lớp 11

1

NL

Nguyễn Lê Phước Thịnh

7 tháng 1

a: $A=\dfrac{9^4}{3^2}=\dfrac{\left(3^2\right)^4}{3^2}=\dfrac{3^8}{3^2}=3^6$=729

b: $B=81\left(\dfrac{5}{3}\right)^4=81\cdot\dfrac{5^4}{3^4}=\dfrac{81}{3^4}\cdot5^4=5^4=625$

c: $C=\left(\dfrac{4}{7}\right)^{-4}\cdot\left(\dfrac{2}{7}\right)^3$

$=\left(\dfrac{7}{4}\right)^4\cdot\left(\dfrac{2}{7}\right)^3$

$=\dfrac{7^4}{4^4}\cdot\dfrac{2^3}{7^3}$

$=\dfrac{2^3}{4^4}\cdot7$

$=\dfrac{2^3}{2^8}\cdot7=\dfrac{7}{2^5}=\dfrac{7}{32}$

d: $D=7^{-6}\cdot\left(\dfrac{2}{3}\right)^0\left(\dfrac{7}{5}\right)^6$

$=7^{-6}\left(\dfrac{7}{5}\right)^6$

$=\dfrac{1}{7^6}\cdot\dfrac{7^6}{5^6}=\dfrac{1}{5^6}=\dfrac{1}{15625}$

e: $E=8^3:\left(\dfrac{2}{3}\right)^5\cdot\left(\dfrac{1}{3}\right)^2$

$=2^6:\dfrac{2^5}{3^5}\cdot\dfrac{1}{3^2}$

$=2^6\cdot\dfrac{3^5}{2^5}\cdot\dfrac{1}{3^2}$

$=\dfrac{2^6}{2^5}\cdot\dfrac{3^5}{3^2}=3^3\cdot2=54$

f: $F=\left(\dfrac{7}{9}\right)^{-2}\cdot\left(\dfrac{1}{\sqrt{3}}\right)^8$

$=\left(\dfrac{9}{7}\right)^2\cdot\left(\dfrac{1}{3}\right)^4$

$=\dfrac{9^2}{7^2}\cdot\dfrac{1}{3^4}=\dfrac{9^2}{3^4}\cdot\dfrac{1}{7^2}=\dfrac{81}{81}\cdot\dfrac{1}{49}=\dfrac{1}{49}$

g: $G=\left(-\dfrac{4}{5}\right)^{-2}\cdot\left(\dfrac{2}{5}\right)^2\cdot\left(\sqrt{2}\right)^3$

$=\left(-\dfrac{5}{4}\right)^2\cdot\left(\dfrac{2}{5}\right)^2\cdot2\sqrt{2}$

$=\dfrac{25}{16}\cdot\dfrac{4}{25}\cdot2\sqrt{2}=\dfrac{4}{16}\cdot2\sqrt{2}=\dfrac{8\sqrt{2}}{16}=\dfrac{\sqrt{2}}{2}$

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SG

Sách Giáo Khoa

18 tháng 4 2017

Tìm giá trị của các biểu thức sau :

$P=\left(-0,5-\dfrac{3}{5}\right):\left(-3\right)+\dfrac{1}{3}-\left(-\dfrac{1}{6}\right):\left(-2\right)$

$Q=\left(\dfrac{2}{25}-1,008\right):\dfrac{4}{7}:\left[\left(3\dfrac{1}{4}-6\dfrac{5}{9}\right).2\dfrac{2}{17}\right]$

1

LH

Lưu Hạ Vy

18 tháng 4 2017

$P=\left(0,5-\dfrac{3}{5}\right):\left(-3\right)+\dfrac{1}{3}-\left(-\dfrac{1}{6}\right):\left(-2\right)$

$=\left(-\dfrac{1}{2}-\dfrac{3}{5}\right):\left(-3\right)+\dfrac{1}{3}-\left(-\dfrac{1}{6}\right).\left(-\dfrac{1}{2}\right)$

$=\left(\dfrac{-5-6}{10}\right):\left(-3\right)+\dfrac{1}{3}-\dfrac{1}{12}$

$=-\dfrac{11}{10}:\left(-3\right)+\dfrac{1}{4}$

$=-\dfrac{11}{10}.\left(-\dfrac{1}{3}\right)+\dfrac{1}{4}=\dfrac{11}{30}+\dfrac{1}{4}=\dfrac{37}{60}$

Vậy $P=\dfrac{37}{60}$

$Q=\left(\dfrac{2}{25}-1,008\right):\dfrac{4}{7}:\left[\left(3\dfrac{1}{4}-6\dfrac{5}{9}\right):2\dfrac{2}{17}\right]$

$=\left(\dfrac{2}{25}-\dfrac{126}{125}\right):\dfrac{4}{7}:\left[\left(\dfrac{13}{4}-\dfrac{59}{9}\right).\dfrac{36}{17}\right]$

$=-\dfrac{116}{125}.\dfrac{7}{4}:\left(-\dfrac{119}{36}.\dfrac{36}{17}\right)$

$=\dfrac{-29.7}{125}:\left(-7\right)=\dfrac{29}{125}$

Vậy $Q=\dfrac{29}{125}$

LN

Lê Ngọc Anh

17 tháng 3 2022

Tính giá trị của biểu thức sau:

$\dfrac{6}{7}+\dfrac{5}{8}:5-\dfrac{3}{16}.\left(-2\right)^2$

$\dfrac{2}{3}+\dfrac{1}{3}.\left(-\dfrac{4}{9}+\dfrac{5}{6}\right):\dfrac{7}{12}$

#Toán lớp 6

1

DC

dâu cute

17 tháng 3 2022

$\dfrac{6}{7}+\dfrac{5}{8}:5-\dfrac{3}{16}.\left(-2\right)^2=\dfrac{6}{7}+\dfrac{5}{8}:5-\dfrac{3}{16}.4=\dfrac{6}{7}+\dfrac{1}{8}-\dfrac{3}{4}=\dfrac{5}{56}$

$\dfrac{2}{3}+\dfrac{1}{3}.\left(-\dfrac{4}{9}+\dfrac{5}{6}\right):\dfrac{7}{12}=\dfrac{2}{3}+\dfrac{1}{3}.\dfrac{7}{18}:\dfrac{7}{12}=\dfrac{2}{3}+\dfrac{2}{9}=\dfrac{8}{9}$

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TD

Thầy Đức Anh

Giáo viên VIP

27 tháng 4 2022

Tính giá trị của các biểu thức sau theo cách hợp lí nhất.
a) $P=\dfrac{2}{3}-\left(-\dfrac{1}{4}\right)+\dfrac{3}{5}-\dfrac{7}{45}-\left(-\dfrac{5}{9}\right)+\dfrac{1}{12}+\dfrac{1}{35}$;
b) $Q=\left(5-\dfrac{3}{4}+\dfrac{1}{5}\right)-\left(6+\dfrac{7}{4}-\dfrac{8}{5}\right)-\left(2-\dfrac{5}{4}+\dfrac{16}{5}\right)$.

14

PT

Phạm Trường Giang

VIP

22 tháng 6 2022

a) $P = \frac{2}{3} + \frac{1}{4} + \frac{3}{5} - \frac{7}{45} + \frac{5}{9} + \frac{1}{12} + \frac{1}{35}$ $= (\frac{2}{3} + \frac{1}{4} + \frac{1}{12}) + (\frac{5}{9} - \frac{7}{45}) + \frac{3}{5} + \frac{1}{35} = 1 + \frac{4}{5} + \frac{3}{5} + \frac{1}{35} = 2 \frac{1}{35}$

T

TINH

14 tháng 7 2022

$P = \frac{2}{3} + \frac{1}{4} + \frac{3}{5} - \frac{7}{45} + \frac{5}{9} + \frac{1}{12} + \frac{1}{35}$

P $= (\frac{2}{3} + \frac{1}{4} + \frac{1}{12}) + (\frac{5}{9} - \frac{7}{45}) + \frac{3}{5} + \frac{1}{35} = 1 + \frac{4}{5} + \frac{3}{5} + \frac{1}{35} = 2 \frac{1}{35}$

P = $= (\frac{2}{3} + \frac{1}{4} + \frac{1}{12}) + (\frac{5}{9} - \frac{7}{45}) + \frac{3}{5} + \frac{1}{35} = 1 + \frac{4}{5} + \frac{3}{5} + \frac{1}{35} = 2 \frac{1}{35}$ .

b)

$Q = (5 - \frac{3}{4} + \frac{1}{5}) - (6 + \frac{7}{4} - \frac{8}{5}) - (2 - \frac{5}{4} + \frac{16}{5})$

$Q = (5 - \frac{3}{4} + \frac{1}{5}) - (6 + \frac{7}{4} - \frac{8}{5}) - (2 - \frac{5}{4} + \frac{16}{5})$ )

$Q = (5 - 6 - 2) + (- \frac{3}{4} - \frac{7}{4} + \frac{5}{4}) + (\frac{1}{5} - \frac{8}{5} - \frac{16}{5}) = - (3 + \frac{5}{4} + \frac{23}{5})$ $= - (3 + 1 \frac{1}{4} + 4 \frac{3}{5}) = - 8 \frac{17}{20}$

$= - (3 + 1 \frac{1}{4} + 4 \frac{3}{5}) = - 8 \frac{17}{20}$ .

T

Top1phiphaiVinh_Phuc

21 tháng 9 2023

a)$0,5+\dfrac{1}{3}+0,4+\dfrac{5}{7}-\dfrac{1}{6}-\dfrac{4}{35}$
b)$\left(3-\dfrac{1}{4}+\dfrac{2}{3}\right)-\left(5+\dfrac{1}{3}-\dfrac{6}{5}\right)-\left(-6-\dfrac{7}{4}+\dfrac{3}{2}\right)$
c)$\dfrac{1}{3}-\dfrac{3}{4}-\left(-\dfrac{3}{5}\right)+\dfrac{1}{64}-\dfrac{2}{9}-\dfrac{1}{36}+\dfrac{1}{15}$

1

NM

Nguyễn Minh Dương

VIP

21 tháng 9 2023

$a,0,5+\dfrac{1}{3}+0,4+\dfrac{5}{7}-\dfrac{1}{6}-\dfrac{4}{35}\\ =\dfrac{1}{2}+\dfrac{1}{3}+\dfrac{2}{5}+\dfrac{5}{7}-\dfrac{1}{6}-\dfrac{4}{35}\\ =\dfrac{5}{6}+\dfrac{39}{35}-\dfrac{1}{6}-\dfrac{4}{35}\\ =\left(\dfrac{5}{6}-\dfrac{1}{6}\right)+\left(\dfrac{39}{35}-\dfrac{4}{35}\right)\\ =\dfrac{2}{3}+1\\ =\dfrac{4}{3}.$

$b,\left(3-\dfrac{1}{4}+\dfrac{2}{3}\right)-\left(5+\dfrac{1}{3}-\dfrac{6}{5}\right)-\left(-6-\dfrac{7}{4}+\dfrac{3}{2}\right)\\ =3-\dfrac{1}{4}+\dfrac{2}{3}-5-\dfrac{1}{3}+\dfrac{6}{5}+6+\dfrac{7}{4}-\dfrac{3}{2}\\ =\left(3-5+6\right)+\left(-\dfrac{1}{4}+\dfrac{7}{4}\right)+\left(\dfrac{2}{3}-\dfrac{1}{3}\right)+\left(\dfrac{6}{5}+\dfrac{7}{4}\right)\\ =4-\dfrac{3}{2}+\dfrac{1}{3}+\dfrac{59}{20}\\ =\dfrac{5}{2}+\dfrac{1}{3}+\dfrac{59}{20}\\ =\dfrac{17}{6}+\dfrac{59}{20}\\ =\dfrac{347}{60}.$

$c,\dfrac{1}{3}-\dfrac{3}{4}-\left(-\dfrac{3}{5}\right)+\dfrac{1}{64}-\dfrac{2}{9}-\dfrac{1}{36}+\dfrac{1}{15}\\ =\dfrac{1}{3}+\dfrac{3}{4}+\dfrac{3}{5}+\dfrac{1}{64}-\dfrac{2}{9}-\dfrac{1}{36}+\dfrac{1}{15}\\ =\left(\dfrac{1}{3}-\dfrac{2}{9}\right)+\left(\dfrac{3}{4}-\dfrac{1}{36}\right)+\left(\dfrac{3}{5}+\dfrac{1}{15}\right)+\dfrac{1}{64}\\ =\dfrac{1}{9}+\dfrac{13}{18}+\dfrac{2}{3}+\dfrac{1}{64}\\ =\dfrac{3}{2}+\dfrac{1}{64}\\ =\dfrac{65}{64}.$