Bài 1:

1: =15+37+52-37-17=52-2=50

2: =38-42+14-25+27+15=62-42+29=20+29=49

Bài 1: Bỏ ngoặc rồi tính

3) (21-32) - (-12+32)=21-32-(-12)-32=21-32+12-32=-31

4) (12+21) - (23-21+10)=12+21-23+21-10=21

5) (57-725) - (605-53)=57-725-605+53=-1220

6) (55+45+15) - (15-55+45)=55+45+15-15+55-45=55+55=110

Bài 2: Tính các tổng sau một cách hợp lí

1) (-37) + 14 + 26 + 37=(-37+37)+(14+26)=0+40=40

2) (-24) +6 + 10 + 24=(-24+24)+(6+10)=0+16=16

3) 15 + 23 + (-25) + (-23)=(15-25)+(23-23)=-10+0=-10

4) 60 + 33 + (-50) + (-33)=(60-50)+(33-33)=10+0=10

5) (-16) + (-209) + (-14) + 209=(-16-14)+(-209+209)=-30+0=-30

6) (-12) + (-13) + 36 + (-11)=(-11-12-13)+36=-36+36=0

=15+37+52-37-17 =(37-37)+52+15-17 =0+52+15-17 =67-17 =50

(38 – 42 + 14) – (25 – 27 – 15) =38-42+14-25+27+15 =27 c. -(21 – 32) – (-12 + 32) =-21+32+12-32 =-9 d. -(12 + 21 – 23) - (23 – 21 + 10) =-12-21+23-23+21-10 =-22 e. (57 – 725) – (605 – 53) =57-725-605+53 =-1220 f. (55 + 45 + 15) – (15 – 55 + 45) =55+45+15-15+55-45 =110

= 1222222222243

32/5 : 32/25 - 27/37 * 32/3

32/5 * 25/32 - 27/37 * 32/3

5 - 288/37

-103/37

a) \(-75+\left(-325\right)+\left|-45\right|-\left(-125\right)\)

\(=-75-325+45+125\)

\(=\left(45+125\right)-\left(75+325\right)\)

\(=170-400\)

\(=-230\)

b) \(62+\left|128\right|-\left|-155\right|-\left|70\right|\)

\(=62+128-155-70\)

\(\Leftrightarrow190-225\)

\(=-35\)

c) \(815+\left[95+\left(-815\right)+\left(-45\right)\right]\)

\(=815+95-815-45\)

\(=\left(815-815\right)+\left(95-45\right)\)

\(=0+50\)

\(=50\)

d) \(5+\left(-7\right)+9+\left(-11\right)+...+25+\left(-27\right)\)

\(=\left(5-7\right)+\left(9-11\right)+...+\left(25-27\right)\)

\(=-2-2-...-2\)

\(=-2.11\)

\(=-22\)

e) \(34+35+36+37-24-25-26-27\)

\(=\left(34-24\right)+\left(35-25\right)+\left(36-26\right)+\left(37-27\right)\)

\(=10+10+10+10\)

\(=40\)

Ths ban

{50:5-45:5}x7

={10-9}x7

=1x7

=7

d,

=6^2x10:{780:[1000-15,625+35x14]}

=6^2x10:{780:[1000-15,625+490]}

=6^2x10:{780:1474,375}

=6^2x10:0,52903772785

=36x10:0,52903772785

=360:0,52903772785

=608,480769232

khum bt câu d, làm đúng chưa?

chắc sai á

16) M = (-32 + 215) - (-30 + 215)

= -32 + 215 + 30 - 215

= (215 - 215) + (30 - 32)

= 0 - 2 = -2

17) N = -5 + (-37 - 45 + 151) - (-37 + 151)

= -5 - 37 - 45 + 151 + 37 - 151

= (151 - 151) - (5+45) + (37 - 37)

= 0 - 50 + 0 = -50

a 475 - ( 75 + 36 ) = 475 - 75 - 36

= 400 - 36

= 364

b 821 - 73 - 27 - 21

= ( 821 - 21 ) - ( 73 + 27 )

= 800 - 100

= 700

a ) 475 - ( 75 + 36 )

= 475 - ( 75 + 35 ) - 1

= ( 475 - 1 ) - 100

= 474 - 100 = 374

b ) 821 - 73 - 27 - 21

= ( 821 - 21 ) - ( 73 + 27 )

= 800 - 100

= 700

c ) \(\frac{37}{25}\div\frac{5}{4}\div\frac{74}{25}\)

\(=\frac{37\cdot2\cdot2\cdot25}{25\cdot5\cdot37\cdot2}\)

\(=\frac{2}{5}\)

c 37/25:5/4:74/25

=37/25 x 4/5 x 25/74

=37 x 4 x 25/5 x 25 x 74

=2/5.

d 6/11 : 4/3  + 5/11 

=(6/11:5/11):(4/3:4/3)

=6/5:1

=6/5