Câu a:

A = 7 2/13 - (5 2/13 + 2 1/2)

A = 7 2/13 - 5 2/13 - 2 1/2

A = 2 - 2 1/2

A = 2 - 2 - 1/2

A = 0 - 1/2

A = -1/2

Câu b:

B = - 3/4 + 25% : (10 3/10 - 9 4/5) - (-1/2)^2

B = - 3/4 + 1/4 : (103/10 - 49/5) - 1/4

B = - 3/4 + 1/4 : (103/10 - 98/5) - 1/4

B = (-3/4 - 1/4) + 1/4 : (1/2)

B = -1 + 1/4 x 2/1

B = -1 + 1/2

B = - 1/2

Câu a:

A = 7 2/13 - (5 2/13 + 2 1/2)

A = 7 2/13 - 5 2/13 - 2 1/2

A = 2 - 2 1/2

A = 2 - 2 - 1/2

A = 0 - 1/2

A = -1/2

Câu b:

B = - 3/4 + 25% : (10 3/10 - 9 4/5) - (-1/2)^2

B = - 3/4 + 1/4 : (103/10 - 49/5) - 1/4

B = - 3/4 + 1/4 : (103/10 - 98/5) - 1/4

B = (-3/4 - 1/4) + 1/4 : (1/2)

B = -1 + 1/4 x 2/1

B = -1 + 1/2

B = - 1/2

-25*72+25*21-49*25

=(-25).(72-21+49)

=(-25).100

=(-2500)

bn nhớ k nha

C =[125.(73-75)]:(-25)2

=125.(-2):(-25).2

=-250:(-50)

=5

E=125.9.(-4).(-8).25.7

=125.(-8).25.(-4).7.9

=-1000.(-100).63

=6300000

C = ( 125 . 73 - 125 . 75 ) : ( -50)

C = 125 .( -2 ) : (-50)

C = -250 : -50

C =  50

G = ( -3 )²+( -5)³: l -5 l

G = 9 + ( -125) : 5

G = 9 + ( -25 )

G= ( -16 )

E = 125 .9.*( -4 ) . ( -8) .25.7

E = 25.5 .( -4 ) .9 .2. ( -4 ) .25 .7

E =( -100 ).10.( -100).63

E = 10000.630

E = 630000

**** mha

a: \(-145\cdot\left(13-57\right)+57\left(10-145\right)\)

\(=-145\cdot13+145\cdot57+57\cdot10-57\cdot145\)

\(=-145\cdot13+57\cdot10\)

=-1885+570

=-1315

b: \(17\left(15-16\right)+16\left(17-20\right)\)

\(=17\cdot15-17\cdot16+16\cdot17-16\cdot20\)

\(=17\cdot15-16\cdot20=255-320=-65\)

c: \(-38\left(25-4\right)+25\left(-4+38\right)\)

\(=-38\cdot25+38\cdot4-25\cdot4+25\cdot38\)

\(=38\cdot4-25\cdot4=4\cdot13=52\)

c: =2012-119+29+119-29

=2012

\(\dfrac{15}{19}\times\dfrac{25}{33}-\dfrac{15}{19}\times\dfrac{14}{33}\)

\(=\dfrac{15}{19}\times\left(\dfrac{25}{33}-\dfrac{14}{33}\right)\)

\(=\dfrac{15}{19}\times\dfrac{11}{33}\)

\(=\dfrac{5}{19}\)

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