a) 78 . 31 + 78 . 24 + 78 . 17 + 22 . 17

= 78 . (31 + 24) + 17 . (78 + 22)

= 78 . 55 + 17 . 100

= 4290 + 1700

= 5990

b) 64 . 14 + 9 . 56

= 64 . 14 + 9 . 14 . 4

= 14 . (64 + 9 . 4)

= 14 . 100

= 1400

cảm ơn bạn nha

hello; how are you

a)

= (64 + 36) + (469 + 31)

= 100 + 500

= 600

36. (146+57) +64 . 200

36.203+64.200

7308+12800

=20108

20108

k cho mk nha

=36.(143+3+57)+64.200

=36.200+36.3+64.200

=(36+64).200+108

=100.200+108

=20000+108=20108

a, 879 + [ 64 + (-879) + 36 ]

= 879 + 64 - 879 + 36

= (879 - 879) + (64 + 36)

= 100

b, -564 + [ (-724) + 564 + 224 ]

= - 564 - 724 + 564 + 224

= (-564 + 564) + (-724 + 224)

= 0 - 500

= 500

c, [ 461 + (-78) + 40 ] + (-461)

= 461 - 78 + 40 - 461

= (461 - 461) + (40 - 78)

= -38

d, [ 53 + (-76) ] - [ -76 - (-53) ]

= 53 - 76 + 76 - 53

= (53 - 53) + (-76 + 76)

= 0

e, 371 + 731 - 271 - 531

= (371 - 271) + (731 - 531)

= 100 + 200

= 300

f, 57+59+60+61-17-18-19-20-21

= (57 - 17) + (59 - 19) + (60 -20) + (61 - 21) - 18

= 40 + 40 + 40 + 40 -18

= 40 *4 - 18

= 160 - 18

= 142

g, 9-10 + 11-12 + 13-14 + 15-16

= (9-10) + (11-12) + (13-14) + (15-16)

= -1 + (-1) + (-1) + (-1)

= -1 * 4

= -4

h, -1-2-3-4-5 ... -1999-2000-2001-2002

i, [ 453 + 64 + (-879) ] + (-517)

= 453 + 64 - 879 - 517

= [(453 + 64) - 517] - 879

= 0 - 879

= -879

j, -323 + [ (-874) + 564 - 241 ]

= -323 - 874 + 564 - 241

= [(-323 - 241) + 564] - 874

= 0 -874

= -874

a: =387-87-224=300-224=76

b: =-75-25+329

=329-100=229

c: =-21-27+31+24=-48+55=7

d: =21(23+17)=21*40=840

e: =12-57+57-12

=0

f: =-6(36+64)=-6*100=-600

\(P=\dfrac{32}{64}\cdot\dfrac{-57}{19}+\dfrac{35}{21}\cdot\dfrac{22}{44}=\dfrac{1}{2}\left(-3+\dfrac{5}{3}\right)=\dfrac{1}{2}\cdot\dfrac{-4}{3}=\dfrac{-2}{3}\)

\(Q=\dfrac{75}{125}\cdot\dfrac{82}{164}+\dfrac{49}{98}\cdot\dfrac{-35}{105}=\dfrac{1}{2}\left(\dfrac{3}{5}-\dfrac{1}{3}\right)=\dfrac{1}{2}\cdot\dfrac{4}{15}=\dfrac{2}{15}\)