1: =20*(-4)+24(-30)

=-80-720=-800

2: =-13*57+13*32+57*13-57*45

=13*32-57*45=-2149

3: =-12*8*125

=-12*1000=-12000

4: =(-134)(1-51+48)

=(-134)*(-2)=268

5: =(-24)(45-5)=40*(-24)=-960

\(\text{35 + (–47) – |–12|}\)

\(=-12-12\)

\(=-24\)

\(\text{(–15) – 70 : (–14) + (–32) . (–2)}\)

\(=-15+5+64\)

\(=-10+64\)

\(=54\)

\(\text{ 15 – 12 . (-3)^2 – 135 : |–15|}\)

\(=15-12.9-135:15\)

\(=15-108-9\)

\(=-102\)

Tính hợp lý:

\(\text{ –24 . 78 + 24(–35) – 24(–13)}\)

\(=24.\left(-78+\left(-35\right)-\left(-13\right)\right)\)

\(=24.\left(-100\right)\)

\(=-2400\)

học tốt

TK

a) (35 - 15).(-4) + 24.(-13 - 17)

= 20.(-4) + 24.(-30)

= (-80) + (-720)

b) (-13).(57 - 34) +57. (13 - 45)

= (-13).23 + 57.(-32)

= (-299) + (-1824) 

= -2123

? TK, bn tự lm cần j TK

a.={75+(-75)}+{15+(-32)}+-55

=0+-17+-55

=0+{(-17)+(-55)

=0+-75

=-75

b. =(35+35)+(65-65)+(24-24)

=70+0+0

=70

không biết đúng hay sai mong mấy bạn thông cảm vì mình cũng không chắc chắn !

1, ( 37 . 13 - 13 . 1 ) : ( 24 + 37 . 12 )

    [ 13 . ( 37 - 1 ) ] : ( 12 . 2 + 37 . 12 )

    ( 13 . 36 ) : [ 12 ( 2 + 37 ) ]

   ( 13 . 36 ) : ( 12 . 36 )

    36

chắc z ^^ 

lm bừa ko cần mt

chac dung do 

a)27*47+13*24+24*10*3

=27*47+13*24+24*30

=27*47+24*(13+30)

=27*47+24*43

=2301

b)

55-50+45-40+35-30+25-20+15-10+5

=(55-50)+(45-40)+(35-30)+(25-20)+(15-10)+5

=5+5+5+5+5+5

=30

a: \(-\frac{10}{3}+\frac{13}{10}-\frac16+\frac{7}{10}\)

\(=\left(-\frac{10}{3}-\frac16\right)+\left(\frac{13}{10}+\frac{7}{10}\right)\)

\(=-\frac{21}{6}+\frac{20}{10}=-\frac72+2=-\frac32\)

b: \(1-\frac{20}{6}+\frac{39}{30}-\frac{4}{24}+\frac{34}{50}\)

\(=1-\frac{20}{6}+\frac16+1,3+0,68\)

\(=1-\frac{19}{6}+1,98=2,98-\frac{19}{6}=\frac{298}{100}-\frac{19}{6}=\frac{-56}{300}=\frac{-14}{75}\)

c: \(\frac{15}{24}-\frac{6}{26}+\frac{28}{48}-\frac{30}{39}+\frac{10}{24}\)

\(=\left(\frac{15}{24}+\frac{10}{24}+\frac{28}{48}\right)-\left(\frac{3}{13}+\frac{10}{13}\right)\)

\(=\left(\frac{25}{24}+\frac{14}{24}\right)-1=\frac{39}{24}-1=\frac{15}{24}=\frac58\)

d: \(-\frac{5}{10}+\frac{12}{28}-\frac{3}{27}-\frac{7}{18}+\frac{20}{35}\)

\(=-\frac12+\frac37-\frac19-\frac{7}{18}+\frac47\)

\(=\left(-\frac12-\frac19-\frac{7}{18}\right)+\left(\frac37+\frac47\right)=-1+1=0\)

02+13+24+35+46+57+68+79+80= 404

Bấm máy tính đêê bà con

a) 35 x 12 + 65 x 13

= 35 x 12 + 65 x (12+1)

=35 x 12 + 65 x 21 + 65

=12 x (65 + 35) + 65

= 12 x 100 + 65

= 1200 + 65

= 1265

b) (37 x 13 -13) : (24 + 37 x 12)

= [ 37 x (12+1) - 13 ] :  (24 + 37 x 12)

=( 37 x 12 + 37 - 13) : ( 24 +37 x 12)

=( 37 x 12 +24) : (24 + 37 x 12)

=\(1\)

Ta có nhận xét phần b hai tích chia cho nhau mà 2 tích giống nhau vậy kết quả là \(1\)

35 x 12 + 65 x 13 = 1265

( 37 x 13 - 13) : (24 + 37 x 12) = 1