\(\frac{42}{-37}va\frac{-56}{43}\)

\(\frac{42}{-37}=\frac{-42}{37}=\frac{-1806}{1591}\)

\(\frac{-56}{37}=\frac{-2408}{1591}\)

Vì\(\frac{-1806}{1591}>\frac{-2408}{1591}\)

=>\(\frac{42}{-37}>\frac{-56}{43}\)

\(\frac{217}{18}va\frac{217}{19}\)

Vì\(\frac{217}{18}>\frac{217}{19}\)

=>\(\frac{217}{18}>\frac{217}{19}\)

\(\frac{-9}{14}va\frac{19}{-25}\)

\(\frac{-9}{14}=\frac{-225}{350};\frac{19}{-25}=\frac{-19}{25}=\frac{-266}{350}\)

Vì\(\frac{-225}{350}>\frac{-266}{350}\)

=>\(\frac{-9}{14}>\frac{19}{-25}\)

Chúc bạn học tốt!

Ta có : \(\frac{217}{18}-1=\frac{199}{18}\)

\(\frac{218}{19}-1=\frac{199}{19}\)

Do \(\frac{199}{18}>\frac{199}{19}\Rightarrow\frac{217}{18}< \frac{218}{19}\)

\(\frac{217}{18}=12+\frac{1}{8}>11+1>11+\frac{9}{19}=\frac{218}{19}\)

217/18 - 1 = 199/18 ; 218/19 - 1 = 199/19

199/18 > 199/19 nên 217/18 > 217/19

Ta có: \(\left(2^{17}+15^4\right)\cdot\left(3^{19}-2^{17}\right)\cdot\left(2^4-4^2\right)\)

\(=\left(2^{17}+15^4\right)\left(3^{19}-2^{17}\right)\cdot\left(16-16\right)\)

=0

tính nhanh

a, (756 - 217) - ( 183 -44)

\(=756-217-183+44\)

\(=\left(756+44\right)+\left(-217-183\right)\)

\(=800-400\)

\(=400\)

b, 11-12+13-14+15-16+17-18+19-20

\(=\left(11+19\right)-\left(12+18\right)+\left(13+17\right)-\left(14+16\right)+\left(15-20\right)\)

\(=30-30+30-30-5\)

\(=-5\)

a) \(\left(756-217\right)-\left(183-44\right)\)

= \(756-217-183+44\)

= \(\left(756+44\right)+\left(-217-183\right)\)

= \(800+\left(-400\right)\)

= \(400\)

b) 11-12+13-14+15-16+17-18+19-20

= (11-12) +(13-14)+(15-16)+(17-18)+(19-20) 

=11-12= -1 
Mà: có 5 cặp số 
Nên: -1*5= -5 

nha

a) 217 x 11

= 217 x (10 +1)

= 217 x 10 + 217 x 1

= 2170 + 217 = 2387

217 x 9 = 217 x (10-1)

= 217 x 10 - 217 x 1

= 2170 - 217 = 1953

b) 413 x 21 = 413 x (20 + 1)

= 413 x 20 + 413 x 1 = 8673

413 x 19 = 413 x (20-1)

= 413 x 20 - 413 x 1 = 7847

c) 1234 x 31 = 1234 x (30 +1)

= 1234 x 30+ 1234 x 1

= 37020 + 1234 = 38254

875 x 29 = 875 x (30 -1)

= 875 x 30 - 875 x 1

= 26250 - 875 = 25375

a) (2345-45)+2345

= 2300 + 2345

= 4645

b) (-2010)-(119-2010)

= -2010-119+2010

= (2010-2010)-199

= -199 

c) (18+29)+(158-18-29)

= 18+29+158-18-29

= (18-18)+(29-29)+158

= 158

d) 126+(-20)+2004+(-106)

= 126 -20 + 2004 - 106

= (126-20-106) +2004

= 2004

e) (-199)+(-200)+(-201)

= -(199+200+201)

= -600

g) 217+ [43+(-217)+(-23)]

= 217+ 43 - 217 + 23

= (217-217)+(43-23)

= 20

-Học tốt-

a/ (- 2010) - (119 - 2010)

= (- 2010) - 119 + 2010

= - 119

b/ 217 + [43 + (- 217) + (- 23)]

= 217 + [43 + (-217) - 23]

= 217 + (-217) + 20

= 20

Bài 2: Tính bằng cách hợp lý nhất:

 a) (-2010) – (119 -2010)

= -2010 - 119 + 2010

= 2010 - 2010 - 119

=     0 - 119

= -119

b) 217 +[ 43 + (-217) +(-23)]

= 217 +  43 - 217 - 23

= ( 217 - 217 ) + ( 43 - 23 )

=        0            + 20

= 20

c) (18+29)+(158 -18 -29)       

= 18 + 29 + 158 - 18 - 29

= ( 18 - 18 ) + ( 29 - 29 ) + 158

=       0        +       0         + 158

= 158

d) 126 +(-20) +2004+(-106)

= 126 - 20 + 2004 - 106

= [( 126 - 20 ) - 106 ] + 2004

= [ 106 - 106 ] + 2004

=      0 + 2004

= 2004

e) (-199) +(-200) +(-201)

= -199 - 200 - 201

= -199 - 201 - 200

= - 400 - 200

= -600

f) 99 + (-100) +101   

= 99 - 100 + 101

= 99 + 101 -100

= 200 - 100

= 100

Sai đề rồi bn ơi!

4-7+10-13+....-2011+2014-2017+2020

=(4-7)+(10-13)+....+(2008-2011)+(2014-2017)+2020    (có 1005 cặp)

=-3+-3+....+-3+2014    (có 1005 số -3)

=-3.1005+2014

=-3015+2014

=-1001

Mik sửa đề lun

753*99 = 753*( 100 - 1 ) 

62*49 = 62*( 50 - 1 )

53*29 = 53*( 30 -1 )

217*11 = 217*( 20 - 9 )

413*21 = 413*(30 -9 )

413*19 = 413*( 20 - 1 )

217*19 = 217*( 20 - 1)

57*9=50*9+7*9

753*99=753*90+753*9

62*49=60*49+2*49

53*29=50*29+3*29

217*11=217*10+217*1

413*21=413*20+413*1

413*19=413*10+413*9

217*19=217*10+217*9

la hieu nha ban nguyen dieu linh