9) -48725 - ( 357 - 48725 ) + 300

= - 48725 + ( - 357) + 48725 + 300

= [ ( - 48725 ) + 48725 ] + [ ( - 357) + 300]

= 0 + ( -57)

= - 57

10) 3579 - ( 49 - 5 + 3579 ) + 49

= 3579 + ( -49) + 5 + ( -3579) +49

= [ 3579 + ( -3579) ] + [ ( - 49) + 49] + 5

= 0 + 0 + 5

= 5

9) - 48275 - ( 357 - 48725 ) + 300

= -48275 - 357 + 48725 +  300

= ( - 48725 + 48725 ) + ( -357 + 300)

= -57

10) 3579- ( 49 - 5 + 3579 ) + 49

= 3579 - 49 + 5 - 3579 + 49

= ( 3579 - 3579) + (-49 + 49) + 5

= 0+0+5= 5

\(a.35-17+1993-35-1993\\ =-17+\left(35-35\right)+\left(1993-1993\right)\\ =-17+0+0\\ =-17\\ b.-48725-\left(357-48725\right)+300\\ =-48725-357+48725+300\\ =\left(300-357\right)+\left(48725-48725\right)\\ =-57+0\\ =-57\\ c.3579-\left(49-5+3579\right)+49\\ =3579-49+5-3579+49\\ =5+\left(3579-3579\right)+\left(49-49\right)\\ =5+0+0\\ =5\)

a) \(35-17+1993-35-1993\)

\(=\left(35-35\right)+\left(1993-1993\right)-17\)

\(=-17\)

b) \(-48725-\left(357-48725\right)+300\)

\(=\left(-48725+48725\right)+\left(300-357\right)\)

\(=-57\)

c) \(3579-\left(49-5+3579\right)+49\)

\(=\left(3579-3579\right)+\left(49-49\right)+5\)

\(=5\)

Tính hợp lí:

a) 35-17+1993-35-1993

=(35-35)+(1993-1993)-17

=-17

b) -48725-(357-48725)+300

=-48725-357+48725+300

=-57

c) 3579-(49-5+3579)+49

=3579-49+5-3579+49

=5

(14568+3579)-(14563+3564)

= 14568+3579-14563-3564

=(14568-14563)+(3579-3564)

=5+15=20

Khi đổi chỗ các số hạng trong một tổng thì tổng đó không thay đổi.

Nên : “4824+3579=3579+4824”.

Vậy Tí nói đúng.

ac vay                 

vay do cau:

2^1000:2013 du may

\(=49\times\left(55+48-3\right)=49\times100=4900\)

= 49 x (55 + 48 - 3)

= 49 x 100

= 4900