\(=\frac{-43}{90}\)\(:\)\(\frac{86}{45}\)

\(=\)\(\frac{-43}{90}\)\(.\)\(\frac{45}{86}\)

\(=\)\(\frac{-1}{4}\).

\(\left(\frac{-5}{6}+\frac{4}{5}-\frac{4}{9}\right)\):\(\frac{86}{45}\)=\(\frac{-43}{90}\):\(\frac{86}{45}\) =\(\frac{-1}{4}\)
 

\(\left(\frac{-5}{6}+\frac{4}{5}-\frac{4}{9}\right):\frac{86}{45}=\frac{-43}{90}:\frac{86}{45}=\frac{-1}{4}\)

123,45 + 23,56 +76,44 + 54,55

= (123,45 + 54,55) + (23,56 + 76,44)

= 178 + 100

= 278

456 x 45 + 456 x 10 + - 456 x 55

=456 x (45 +10-55)

=456 x 0

=0

2,5 x 8,5 + 7,5 x 8,5 

=8,5 x (2,5 +7,5)

= 8,5 x 10

= 85

86 x 5 + 86 x 4 + 86

= 86 x (5+4+1)

= 86 x10

860

25 x 8 x 17 x 50

= 50 x 4 x 17 x 50

= 200 x 17 x 50 

= 200 x 50 x 17

= 10000 x 17

= 170000

(12 x 2 + 12 x 4 - 12 x 6 ) : ( 2 + 4 + 6 +... + 12 +14)

=(12 x (2 + 4 - 6) ) : ( 2 + 4 + 6 + ... + 12 + 14 )
= (12 x 0 ) : (2 + 4 + 6 + ... + 12 + 14 )

=0 : ( 2 + 4 + 6 + ... + 12 + 14)

= 0

a) = 100

b) = 45

a, = (86-6)+(29-9) = 80+20 = 100

b, = (1+9)+(2+8)+(3+7)+(4+6)+5 = 10+10+10+10+5 = 45

k mk nha

a/ =(86-6)+(29-9)=80+20=100

b/=(1+9)+(2+8)+(3+7)+(4+6)+5=10+10+10+10+5=45

45x6=270

1+1+2+2+3+3+4+4+5+5+6+6+7+7+8+8+9+9

=(1x2)+(2x2)+(3x2)+(4x2)+(5x2)+(6x2)+(7x2)+(8x2)+(9x2)

=2+4+6+8+10+12+14+16+18

=6+6+8+10+12+14+16+18

=12+8+10+12+14+16+18

=20+10+12+14+16+18

=30+12+14+16+18

=42+14+16+18

=56+16+18

=72+18

=90

78:5=15(dư3)

45:5=9

x:5=25

   x= 25x5

   x= 125

tk nhé

45 x 6 = 270

1 + 1 + 2 + 2 + 3 + 3 + 4 + 4 + 5 + 5 + 6 + 6 + 7 + 7 + 8 + 8 + 9 + 9

= 2 + 4 + 6 + 8 + 10 + 12 + 14 + 16 + 18

= ( 2 + 18 ) x 9 : 2

= 90

78 : 5 = 15 ( dư 3 )

45 : 5 = 9

x : 5 = 25

    x  = 25 x 5

    x  = 125

\(45x6=270\)

\(1+1+2+2+3+3+4+4+5+5+6+6+7+7+8+8+9+9\)

\(=1.2+2.2+3.2+4.2+5.2+6.2+7.2+8.2+9.2\)

\(=2+4+6+8+10+12+14+16+18\)

\(=\left(2+18\right)+\left(4+16\right)+\left(6+14\right)+\left(8+12\right)+10\)

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

\(=10.5\)

\(=50\)

\(78:5=15\left(du3\right)\)

\(45:5=9\)

\(x:5=25\)

       \(x=25.5\)

      \(x=125\)

Trả lời :

=245

=45

Hok_Tốt

#Thiên_Hy

#)Giải :

145 + 86 + 14 = 245

1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 

= ( 1 + 9 ) + ( 2 + 8 ) + ( 3 + 7 ) + ( 4 + 6 ) + 5

= 10 + 10 + 10 + 10 + 5

= 45

        #~Will~be~Pens~#

a

=145+100=245

b

=(1+9)+(2+8)+(3+7)+(4+6)+5

=10+10+10+5

=35

`4/7+4`

`=4/7+4/1`

`=4/7+28/7`

`=32/7`

__

`3+6/11`

`=33/11+6/11`

`=39/11`

__

`3-5/7`

`=3/1-5/7`

`=21/7-5/7`

`=16/7`

__

`21/9-2`

`=21/9-18/9`

`=3/9`

`=1/3`

__

`15/24+2`

`=15/24+48/24`

`=63/24`

`=21/16`

__

`63/45-20/25`

`=63/45-4/5`

`=63/45-36/45`

`=27/45`

`=9/15`

__

`3/4-2/8`

`=3/4-1/4`

`=2/4`

__

`6/7-5/8`

`=48/56-35/56`

`=13/56`

__

`37/45-5/9`

`=37/45-25/45`

`=12/45`

`=4/15`

__

`46/39-11/13`

`=46/39-33/39`

`=13/39`

`=1/2`

__

`5/12+3/4+1/3`

`=5/12+9/12+4/12`

`=14/12+4/12`

`=18/12`

`=3/2`

__

`1/2+3/7+11/14`

`=7/14+6/14+11/14`

`=13/14+11/14`

`=24/14`

`=12/7`

__

`7/10-(1/5+1/4)`

`=7/10-(4/20+5/20)`

`=7/10-9/20`

`=14/20-9/20`

`=5/20`

`=1/4`

__

`15/4-2/3-3/4`

`=(15/4-3/4)-2/3`

`=12/4-2/3`

`=3-2/3`

`=9/3-2/3`

`=7/3`