-39

-12

tick nha

=(768-768)-39=0-39=-39

=(-1589)-(-157)-12=0-12=-12

a) ( 768 - 39 ) - 768

= 768 - 39 - 768

= ( 768 - 768 ) - 39

= 0 - 39

= -39

b) ( -1579 ) - ( 12 - 1579 )

= -1579 - 12 + 1579

= ( 1579 - 1579 ) - 12

= 0 - 12

= -12

a) ( 768 - 39 ) - 768

= 768 - 39 - 768

= ( 768 - 768 ) - 39

= 0 - 39

= -39

b) ( -1579 ) - ( 12 - 1579 )

= ( -1579 ) - 12 + 1579

= ( -1579 + 1579 ) - 12

= 0 + -12

= -12

a) \(\left(768-39\right)-768=768-39-768=768-768-39=0-39=-39\)

b)\(\left(-1579\right)-\left(12-1579\right)=\left(-1579\right)-12+1579=\left[\left(-1579\right)+1579\right]-12=0-12=-12\)

a. (768 - 39) - 768

= 768 - 39 - 768

= 768 - 768 - 39

= 0 - 39

= -39

b. (-1579) - (12 - 1579)

= (-1579) - 12 + 1579

= [(-1579) + 1579] - 12

= 0 - 12

= -12

chờ mình xíu

a) ( 768 - 39 ) - 768

= ( 768 - 768 ) - 39

= 0 - 39

= -39

a) ( 768 - 39 ) -768

= 768 - 39 - 768

= ( 768 - 768 ) -39

= 0 - 39

= -39

b) ( - 1579 ) - ( 12 - 1579 )

= ( - 1579 ) -12 + 1579

= [ ( -1579 ) + 1579 ] -12

= 0 - 12

= -12

tk mn nha!

a là -39

b là 988

a. (768-39)-768

= 768-39-768

= (768-768)-39

= 0-39=-39

b. (-579)-(12-1579)

= -579-12+1579

= (1579-579)-12

= 1000-12=988.

a) -39

b) 988

tick nha

1a,=-2*3=-6                      b,=2*3=6

2a,=-39         b,=-12

B1 :

a, = -2-2-2= -6

b, = -2-2-2 = -6

B2:a, = 768-39-768 = (768-768)-39=0-39=-39

b, = -1579-12+1579 = (-1579+1579)-12 = 0-12=-12

k mk nha

Bài 1 : Tính : 

a, 1+(-3)+5+(-7)+9+(-11)

= ( -2 ) + 5 + ( -7 ) + 9 + ( -11 )

= 3 + ( -7 ) + 9 + ( -11 )

= ( -4 ) + 9 + ( -11 )

= 5 + ( -11 )

= ( -6 )

b, (-2)+4+(-6)+8+(-10)+12.

= 2 + ( -6 ) + 8 + ( -10 ) + 12

= ( -4 ) + 8 + ( -10 ) + 12

= 4 + ( -10 ) + 12

= 6 + 12

= 18

Bài 2 : Tính nhanh :

a, (768-39)-768

= 768 - 39 - 768

= ( 768 - 768 ) - 39

= 0 - 39

= ( -39 ) 

b, (-1579)-(12-1579).

= ( -1579 ) - 12 + 1579

= [ ( -1579 ) + 1579 ) ] - 12

=  0 - 12

= ( -12 )

768 + 768 = 1 536

786+786=1572

:))

768 + 768 = 768 x 2 = 1536

tk mk nha mk quen nhau mà