66-6+7+23-18-2=(66-6)+(7+23)-(18-2)

                          =60+30+16

                          =106

sai rồi

= 74. k mk nha

66 - 6 + 7 + 23 - 18 + 2

= 60 + 30 - 20

= 90 - 20

= 70

=3(55+18+27)=300

300

\(1+2+3+4+5+...+28+29=\left(1+29\right).29:2=435\)

(1+29)+(2+28)+(3+27)+(4+26)+(5+25)+(6+24)+(7+23)+(8+22)+(9+21)+(10+20)+(11+19)+(12+18)+(13+17)+(14+16)+15

=30+30+30+30+30+30+30+30+30+30+30+30+30+30+15

=30x14+15

=435

[35+65]+[89+11]+[34+66]+[27+73]+[51+49]+[9+91]

=10+10+10+10+10+10=60 dễ mà

35+89+65+34+11+66+27+73+51+09+91+49

=[35+65]+[89+11]+[34+66]+[27+73]+[51+49]+[09+91]

=100+100+100+100+100+100

=100x6

=600

Câu 1. Tính giá trị biểu thức

a) 18 000 + 22 000 – 15 000 

= 40 000 - 15 000

= 25 000

b) (66 265 – 44 526) × 2

= 21739 x 2

= 43478

c) 27 582 + 26 544 : 2

= 27 582 + 13 272

= 40 854                                         

d) 12 458 : 2 × 3

= 6 229 x 3

= 18 687

Câu 2. Điền >, <, =

67 012 ...<... 70 000

20 340 .....<.... 20 430

96 329 ....>..... 95 132

20 306 ...=...... 20 000 + 300 + 6

40 000 + 5 00 + 6 ....<.... 45 006

70 : 7 = 10

28 : 7 =4

30 : 6 = 5

8 : 2 = 9

63 : 7 = 9

42 : 6 = 7

35 : 5 = 6

27 : 3 = 9

14 : 7 = 2

42 : 7 = 6

35 : 7 = 5

56 : 7 = 8.

hruyhy835y6n./ reuy786y7866

\(=390\)

Đề:45+27+65+46+35+73+54+18+27

=(27+73)+(65+35)+(54+46)+(45+27+18)

=100+100+100+90

=390