= -251 . 3 - 281 + 3 . 251 - 1 + 281

ấn nhầm

\(C=\left(-251\cdot3+251\cdot3\right)+\left(-281+281\right)-1=-1\)

\(A=\left(3,1-2,5\right)-\left(-2,5+3,1\right)\)

\(=3,1-2,5+2,5-3,1=0\)

\(B=\left(5,3-2,8\right)-\left(4+5,3\right)\)

\(=5,3-2,8-4-5,3=-6,8\)

\(C=-\left(251.3+281\right)+3.215-\left(1-281\right)\)

\(=-753-281+645-1+281\)

\(=-753+654-1=-100\)

\(D=-\left(\dfrac{3}{5}+\dfrac{3}{4}\right)-\left(\dfrac{-3}{4}+\dfrac{2}{5}\right)\)

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

\(A=\left(3,1-2,5\right)-\left(-2,5+3,1\right)\)

\(=3,1-2,5+2,5-3,1\)

\(=\left(3,1-3,1\right)-\left(2,5-2,5\right)\)

\(=0\)

Vậy \(A=0.\)

\(B=\left(5,3-2,8\right)-\left(4+5,3\right)\)

\(=5,3-2,8-4-5,3\)

\(=\left(5,3-5,3\right)-\left(2,8+4\right)\)

\(=-\dfrac{34}{5}\)

Vậy \(B=\dfrac{-34}{5}.\)

\(C=-\left(251.3+281\right)+3.215-\left(1-281\right)\)

\(=-251.3-281+3.215-1+281\)

\(=-753-\left(281-281\right)+645\)

\(=-753+645=-108\)

Vậy \(C=-108.\)

\(D=-\left(\dfrac{3}{5}+\dfrac{3}{4}\right)-\left(-\dfrac{3}{4}+\dfrac{2}{5}\right)\)

\(=-\dfrac{3}{5}-\dfrac{3}{4}+\dfrac{3}{4}-\dfrac{2}{5}\)

\(=\left(\dfrac{-3}{5}-\dfrac{2}{5}\right)-\left(\dfrac{3}{4}-\dfrac{3}{4}\right)\)

\(=-1\)

Vậy D = -1.

A=(3,1-2,5)-(-2,5+3,1)
A=3,1-2,5=2,5-3,1

A=(3,1-3,1)+(2,5-2,50

A=0

B=(5,3-2,8)-(4+5,3)

B=5,3-2,8-4-5,3

B=(5,3-5,3)-(4+2,8)

B=0-6,8

B=-6,8

C=-(251.3+281)+3.215-(1-281)

C=-251.3-281+3.215-1+281

C=3(-251+215)-(281+281)-1

C=-108-1

C=-109
D=\(-\left(\dfrac{3}{5}+\dfrac{3}{4}\right)-\left(-\dfrac{3}{4}\right)+\dfrac{2}{5}\)
\(D=-\dfrac{3}{5}+-\dfrac{3}{4}+\dfrac{3}{4}+\dfrac{2}{5}\)

D=\(\left(-\dfrac{3}{5}+\dfrac{2}{5}\right)+\left(-\dfrac{3}{4}+\dfrac{3}{4}\right)\)

\(D=\dfrac{-1}{5}\)

C = - (251.3 + 281) + 3.251 – (1- 281)

= -251.3 -281 + 251.3 -1 + 281

= (-251.3 + 251.3 )+ ( -281 + 281) -1

= 0 + 0 - 1 = -1.

a) -(251 x3 + 281) + 3x 251- (1-281)                                b) \(-\left(\frac{3}{54}+\frac{3}{4}\right)-\left(\frac{-3}{4}+\frac{2}{5}\right)\)

=-251x3 - 281+3 x 251- 1+ 281                                          =\(\frac{-1}{18}-\frac{3}{4}+\frac{3}{4}-\frac{2}{5}\)

=[(-251 x 3)+ (3 x 251)]+(281-281) -1                                 = (\(\frac{3}{4}-\frac{3}{4}\))-(\(\frac{2}{5}+\frac{1}{18}\))

=0+ 0-1                                                                           =0 -41/ 90

                                                                                       =\(-\frac{41}{90}\)

= -1

Bài làm:

Ta có: \(-\left(251.3+281\right)+3.251-\left(1-281\right)\)

\(=-251.3-281+3.251-1+281\)

\(=\left(-251.3+251.3\right)+\left(281-281\right)-1\)

\(=0-0-1=-1\)

- (251 * 3 + 281) + 3 * 251 - (1 - 281)

= -( 753+281) + 753 - -280

= -1034 + 753 - -280

= -281- -280

= -561

Ta có:-(251×3+281)+3×251-(1-281)

=-1034+753+280

=-281+281

=-1

Học tốt

-(251 . 3 + 281) + 3 .251 - (1 - 281 )

= -251 . 3 - 281 + 3 . 251 - 1 + 281

= ( 3 . 251 - 251 . 3 ) + ( 281 - 281 ) -1

= 0 + 0 - 1 = - 1

dễ mà bạn !!!

\(A=-(251.3+281)+3.251-(1-281)\)

\(A=(-251.3)+(-281)+251.3-1+281\)

\(A=3(-251+251)+(-281+281)-1\)

\(A=3.0+0-1\)

\(A=0-1\)

\(A=-1\)

\(A=-\left(251.3+281\right)+3.251-\left(1-281\right)\)

\(A=-251.3-281+251.3-1+281\)

\(A=\left(-251.3+251.3\right)+\left(-281+281\right)-1\)

\(A=-1\)

Chúc bạn học tốt!!!

A= (3,1 - 2,5) - (-2,5 + 3,1)

=3.1-2.5+2.5-3.1

=0

B= (5,3 - 2,8) - (4 + 5,3)

=5.3 - 2.8-4-5.3

= -6.8

C= -(251.3 + 281) + 3.251 - (1-281)

=-251.3-281+3.251-1+281

=-1

D= -(3/5+3/4)−(−3/4+2/5)

= -3/5-3/4+3/4-2/5

= -5/5

=-1

\(A=\left(3,1-2,5\right)-\left(-2,5+3,1\right)=3,1-2,5+2,5-3,1=0\)

\(B=\left(5,3-2,8\right)-\left(4+5,3\right)=5,3-2,8-4-5,3=-6,8\)

\(C=-\left(215\cdot3+281\right)+3\cdot215-\left(1-281\right)=-215\cdot3-281+3\cdot215-1+281=1\)

\(D=-\left(\frac{3}{5}+\frac{3}{4}\right)-\left(-\frac{3}{4}+\frac{2}{5}\right)=-\frac{3}{5}-\frac{3}{4}+\frac{3}{4}-\frac{2}{5}=-1\)

Bài 1 : Tính giá trị của các biểu thức sau đã bỏ dấu ngoặc :

A= (3,1 - 2,5) - (- 2,5 + 3,1) = 3,1 - 2,5 + 2,5 - 3,1 = 0

B= (5,3 - 2,8) - (4 + 5,3) = 5,3 - 2,8 - 4 - 5,3 = - 6,8

C= - (251.3 + 281) + 3.251 - (1 - 281) = - 753 - 281 + 753 + 280 = - 1

D= - (35 + 34) − ( − 34 + 25) = - 35 - 34 + 34 - 25 = - 60

-(3251+415)-(2000+585-251) 

= -3251-415-2000-585+251

=(-3251+251)+(415+585)+2000

=-3000 + 1000 + 2000

=0

k cho mk nhoa 

Quy tắc bỏ dấu ngoặc các bạn nhé!

-(3251+415)-(2000+585-251)

=-3251+415-2000-585+251

=(-3251+251)+(415+585)+2000

=-3000+1000+2000

=0

Học tốt nha bạn