Ta có :

-251.3-281+3.251-1+281

=-281-1+281

=-1

:)) đây nhé bạn

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

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

\(=3.\left(251-251\right)+\left(-281+281\right)-1\)

\(=3.0+0-1\)

\(=-1\)

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

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

= - 753 - 281 + 753 - 1 + 281

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

= 0 - 0 - 1 = -1 

\(B=-\left(251+281\right)+3,251-\left(1-281\right)\)

\(B=-532+3,251-\left(1-28\right)\)

\(B=-532+3,251-\left(-27\right)\)

\(B=3783-\left(-27\right)\)

\(B=3810\)

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

\(=-\left(753+281\right)+753-1+281\)

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

\(=\left(-753+753\right)-\left(-281+281\right)-1\)

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

Học tốt nhé!k mình ngăn!

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

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

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

\(A=0-0\)

\(A=0\)

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

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

\(B=\left(5,3-5,3\right)-\left(2,8+4\right)\\ B=0-6,8\\ B=-6,8\)

Tính giá trị:

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

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

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

\(C=\left[-\left(251.3\right)+3.251\right]+\left[281-\left(1-281\right)\right]\\ C=0+560\\ C=560\)

\(D=-\left(\dfrac{3}{5}+\dfrac{3}{4}\right)-\left(-\dfrac{3}{4}+\dfrac{2}{5}\right)\\ D=-\dfrac{3}{5}-\dfrac{3}{4}+\dfrac{3}{4}-\dfrac{2}{5}\\ D=\left(-\dfrac{3}{5}-\dfrac{2}{5}\right)+\left(-\dfrac{3}{4}+\dfrac{3}{4}\right)\\ D=-1+0\\ D=-1\)

1a, (-3,8) + [ (-5,7)+3,8]

= (-3,8+3,8) -5,7

= -5,7

b, 31,4 +[6,4 +(-18)]

= 31,4 - 11,6

= 19,8

c,[(9,6 )+4,5 ] +[9,6 +(-1,5)]

= 9,6 +9,6 +(4,5-1,5)

= 19,2 +3

=22,2

d, [ (-4,9) + (-7,8)] +[1,9+2,8]

= (-4,9 +1,9)+ (-7,8+2,8)

= -3 -5

=-8

e, (3,1-2,5)-(-2,5+3,1)

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

=0

f, (5,3 -2,8 )- (4+5,3)

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

= -6,8

g, -(251,3 +281 )+ 3,251 -(1-281)

= -251,3-281+3,251 -1+281

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

= -249,049

h,-(3/54+3/4)-(-3/4 +2/5)

= -3/54-3/4 +3/4 +2/5

=(-3/4+3/4) -3/54 +2/5

=123/270

chúc bạn học tốt

lấy mt bấm phắt là ra

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

\(=3,1-2,5+2,5-3,1=6,2\)

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

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

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

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

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

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

(Nhớ k cho mình với nhá!)

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

−(251,3 + 218 )+ 3,251 − ( 1 − 281)

= -469.3 + 3.251 - (-280)

= -469.3 + 3.251 + 280

= -466.049 + 280

= -186.049

lấy casio mà tính cho nhanh

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