\(\frac{17}{25}\times\frac{13}{19}+\frac{17}{25}\times\frac{6}{19}\)

\(=\frac{17}{25}\times\left(\frac{13}{19}+\frac{6}{19}\right)\)

\(=\frac{17}{25}\times\frac{19}{19}\)

\(=\frac{17}{25}\times1\)

\(=\frac{17}{25}\)

_HT_

\(\dfrac{17}{25}\left(\dfrac{13}{19}+\dfrac{6}{19}\right)\)

\(=\dfrac{17}{25}.1=\dfrac{17}{25}\)

a) \(\left(-17\right)\cdot32+17\cdot\left(-68\right)-17\)

\(=17\cdot\left(-32-68-1\right)\)

\(=17\cdot\left(-101\right)\)

\(=17\cdot\left(-100-1\right)\)

\(=-1700-17\)

\(=-1717\)

b) \(25\cdot\left(34-89\right)+25\cdot89\)

\(=25\cdot\left(34-89+89\right)\)

\(=25\cdot34\)

\(=850\)

c) \(-145\cdot\left(13-57\right)+57\cdot\left(10-145\right)\)

\(=-145\cdot13+145\cdot57+57\cdot10-145\cdot57\)

\(=-145\cdot\left(13+57\right)+57\cdot\left(145+10\right)\)

\(=-145\cdot70+57\cdot155\)

\(=-10150+8835\)

\(=-1315\)

`@` `\text {Ans}`

`\downarrow`

`a)`

\((- 17) . 32 + 17 . (- 68) – 17 \)

`= (-17). (32 + 68 + 1) `

`= (-17). 101`

`= -1717`

`b)`

\(25 . (34 – 89) + 25 . 89\)

`= 25. (34 - 89 + 89)`

`= 25. 34`

`= 850`

`c)`

\(– 145. (13 – 57) + 57. (10 – 145)\)

`= (-145). 13 - (-145). 57 + 57.10 + 57. (-145)`

`= (-145). (13 - 57 + 57) + 57.10`

`= (-145). 13 + 570`

`= -1885 + 570 = -1315`

1. 25 + (-8) + (-25) + (-2)

= [ 25 + (-25) ] + [ (-8) + (-2) ]

= 0 + (-10)

= -10

2. (-23) + 13 + (-17) + 57

= [ (-23) + (-17) ] + ( 13 + 57 )

= (-40) + 70

= 30

25+(-8)+(-25)+(-2)=-10

-23+13+(-17)+57= 30

a .   3 10 + 2 5 = 3 10 + 4 10 = 7 10

b .   2 5 - 1 3 = 1 x 1 8 x 4 = 1 32

c .   1 8 x 1 4 = 6 15 - 5 15 = 1 15

d .   1 7 : 3 4 = 1 7 x 4 3 = 4 21

\(\dfrac{17}{8}-\dfrac{13}{25}-\dfrac{12}{25}+\dfrac{15}{8}=\dfrac{17+15}{8}+\dfrac{-13-12}{25}=\dfrac{32}{8}+\dfrac{-25}{25}=4-1=3\)

3

3

= (17/8 + 15/8) - (13/25 + 12/25)

= 4 - 1

= 3

a) 2 + (-25) + 41+ (-2) + 25 +(-41)

= (-2 + 2) + (-25 + 25) + (-41 +41)

=0 + 0 + 0

=0

b) 10+ ( -17) +5 + (-7)+ 17 + (-15)

= (-15+10+5) + (-17+7) + 7

= 0 + 0 + 7

= 7

c)(-22) + (-14) + 17 + (-24) + 13+ 30

= [(-22) + (-14) + (-24)] + (17 + 13 + 30)

=-60 + 60

=0

a) 2 + (-25) + 41+ (-2) + 25 +(-41)

= (-2 + 2) + (-25 + 25) + (-41 +41)

=0 + 0 + 0

=0

2. Tính (+5) + ( +4) = 9

3.Tính (- 9) + ( - 1) = -10

4.Tính : 28 + (-15) = 13

5.Tính (-15) + 12 = - 3

6.Tính (-25) + 25 = 0

7.Tính : 13 - 17 = - 4

8.Tính : (-78) - 9 = - 87

9.Tính : ( -24) - ( - 16) = - 8

10.Tính : 17 - (-3) = 20

11.Tính nhanh : (-21) - ( 48 + 52 - 21) = -100

2,  (+5)+(+4)=+9 hoạc 9 cũng được

3,  (-9)+(-1)=-10

4,  28+(-15)=13

5,  (-15)+12=-3

6,  (-25)+25=0

7,  13-17=4

8,   (-78)-9=-87

9,  (-24)-(-16)=-40

10, 17-(-3)=20

11,  (-21+21)-(48-52)=-4

a) 12 + 13 + 14 - 15 - 16 - 17

= (12 - 15) + (13 - 16) + (14 - 17)

= (-3) + (-3) + (-3) = -9

b) (35 - 17) - (25 - 7 + 22)

= 35 - 17 - 25 + 7 - 22

= (35 - 25) - (17 - 7) - 22

= 10 - 10 - 22 = -22