1: =66+34-73-27+99=99

2: =54-45+30-54-30+5=-40

3: =42-56+33-33+56-42=0

4: =50-47-50+18+47-18=0

5: =10-28+30-4=2-4+10=12-4=8

\(\text{1.-(-66)+34+(-73)-27+99}.\)

\(=66+34-73-27+99=100-100+99=-99.\)

\(\text{2.54-(45-30+54)-30+5}.\)

\(54-45+30-54-30+5=\left(54-54\right)+\left(-45+5\right)+\left(30-30\right)=-40.\)

\(\text{3.42-56+33-(33-56+42)}.\)

\(=42-56+33-33+56-42=\left(42-42\right)+\left(-56+56\right)+\left(33-33\right)=0.\)

\(\text{4.50-(47+50-18)+(47-18)}.\)

\(=50-47-50+18+47-18=\left(50-50\right)+\left(-47+47\right)+\left(18-18\right)=0.\)

\(\text{5.10-(28-30+4)}.\)

\(=10-28+30-4=10+30-20-8-4=20-12=8.\)

\(\text{6.-(-73)+(44-94+27)+94}.\)

\(=73+44-94+27+94=\left(73+27\right)+\left(-94+94\right)+44=100+44=144.\)

= 492309

thông cảm nha, mk chỉ vít đc như zậy thui, diễn giải ra dài dòng lắm

492309

1 2 + − 1 2 + − 2 3 + 2 3 + 3 4 + − 3 4 + − 4 5 + 4 5 + 5 6 + − 5 6 = 0

1 2 + − 1 2 + − 2 3 + 2 3 + 3 4 + − 3 4 + − 4 5 + 4 5 + 5 6 + − 5 6 = 0

Đây nha

a) 12 + 23 + 34 + 45 + 56 + 67 + 78 + 89

= ( 12 + 78 ) + ( 23 + 67 ) + ( 34 + 56 ) + ( 45 + 89 )

= 90 + 90 + 90 + 132

= 90 x 3 + 132

= 270 + 132

= 402

b) 125 x 6 x 7 x 8

= 750 x 7 x 8

= 5250 x 8

= 42000

c) ( 56 x 78 + 56 x 47 ) : 7 

= 56 x ( 78 + 47 ) : 7

= 56 x 125 : 7

= 7000 : 7

= 1000

a) 12 + 23 + 34 + 45 + 56 + 67 + 78 + 89

= ( 12 + 78 ) + ( 23 + 67 ) + ( 34 + 56 ) + ( 45 + 89 )

= 90 + 90 + 90 + 132

= 90 x 3 + 132

= 270 + 132

= 402

b) 125 x 6 x 7 x 8

= 750 x 7 x 8

= 5250 x 8

= 42000

c) ( 56 x 78 + 56 x 47 ) : 7 

= 56 x ( 78 + 47 ) : 7

= 56 x 125 : 7

= 7000 : 7

= 1000

sakura

Tính nhanh:

  a) 56 x 44 + 56 x 11 + 56 x 45

= 56 x ( 44 + 11 + 45 )

= 56 x 100

= 5600 

b) 8 x 3 + 8 x 6 + 8

= 8 x ( 3 +  6 + 1 ) 

= 8 x 10

= 80

^^ Học tốt!!!

a, 56 x 44 + 56 x 11 + 56 x 45

= 56 x ( 44 + 11 + 45 )

= 56 x 100

= 5600

b, 8 x 3 + 8 x 6 + 8

= 8 x ( 3 + 6 + 1 )

= 8 x 10

= 80

x=-538

56 + 34 = 90

56 + 45 = 101 

  Chúc bn hok tốt

\(56+34=90\)

\(56+45=101\)

hok tốt

a) 5 13 + − 5 7 + − 20 41 + 8 13 + − 21 41 = 5 13 + 8 13 + − 20 41 + − 21 41 + − 5 7 = − 5 7

b) 1 28 + − 1 14 + 3 28 + − 1 7 + 3 14 = 1 28 + 3 28 + − 1 14 + 3 14 + − 1 7 = 1 7

c)  1 2 + − 2 3 + 3 4 + − 4 5 + 5 6 + − 5 6 + 4 5 + − 3 4 + 2 3 + − 1 2 = 1 2 + − 1 2 + 3 4 + − 3 4 + − 4 5 + 4 5 + 5 6 + − 5 6 = 0

256,23 + 12,56 = 268,79

56,23 + 12,45 = 68,68

89,67 - 23,45 = 66,22

1,23 + 34,67 = 35,9

19,56 + 45,65 = 65,21

kp voi : http://olm/thanhvien/gop123 va mih dj

123 x 56 + 100 x 44 - 56 x 123

= 100 x 44

= 4400

2 + 4 + 6 + 8 + .... + 24 có số số hạng là:

               (24 - 2) : 2 + 1 = 12 (số)

tổng là : 

               (24 + 2) x 12 : 2 = 156