正負數一問

(正負得負) (負負得正) (負正得正) (正正得負)

1. (+2)+(+1)+(-5)
= +2+1-5
= +3-5
= -2
2. (+5)+(-8)+(+3)
= +5-8+3
= -3+3
= 0
3. (-1)+(-2)+(-4)
= -1-2-4
= -3-4
= -7
4. (+9)+(-3)+(-7)
= +9-3-7
= +6-7
= -1
5. (+8)-(+7)-(-5)
= +8-7+5
= -1+5
= +4
6. (-6)-(-9)-(+4)
= -6+9-4
= +3-4
= -1
7. -16+(+23)+(-2)
= -16+23-2
= +7-2
= +5
8. 5-(-14)-(+30)
= 5+14-30
= +19-30
= -11
9. -3-(-19.3)+0.5
= -3+19.3+0.5
= 16.3+0.5
= 16.8
10. (-7.2)-(+2.3)+(-5)
= -7.2-2.3-5
= -9.5-5
= -14.5
--------------------------------
1. (-81) / (-27)
= 81/27
= 3
2. (+225) / (+5)
=225/5
=45
3. (-231) / (+11)
= -(231)/(11)
= -21
4. (-28) / (+2) / (+7)
= -14/7
=-2
5. (+42) / (+3) / (-21)
= 14/ (-21)
= -14/21
6. (+36) / (-2)(+6)
= +36/-12
= -3
7. (+4)x(-6) / (-12)
= -24/-12
= 2
8. (-7)x(+3) / (-21)
= -21/(-21)
= +1
9. (-45) / (-9)x(-7)
= 5x-7
= -35

1. (+2)+(+1)+(-5)
＝2+1-5
= - 2

2. (+5)+(-8)+(+3)
=5-8+3
=0

3. (-1)+(-2)+(-4)
= - 1-2-4
= - 7

4. (+9)+(-3)+(-7)
=9-3-7
= - 1

5. (+8)-(+7)-(-5)
=8-7+5
=6

6. (-6)-(-9)-(+4)
= - 6+9-4
= - 1

7. -16+(+23)+(-2)
= - 16+23-2
=5

8. 5-(-14)-(+30)
=5+14-30
= - 11

9. -3-(-19.3)+0.5
=-3+19.3+0.5
=16.8

10. (-7.2)-(+2.3)+(-5)
= - 7.2 - 2.3 - 5
= - 14.5
--------------------------------
1. (-81) / (-27)
=81/27
=3

2. (+225) / (+5)
=225/5
=45

3. (-231) / (+11)
= - 231/11
= - 21

4. (-28) / (+2) / (+7)
= - 28/2/7

5. (+42) / (+3) / (-21)
= - 42/3/21

6. (+36) / (-2)(+6)
= - 36/12
= - 3

7. (+4)x(-6) / (-12)
=24/12
=2

8. (-7)x(+3) / (-21)
=21/21
=1

9. (-45) / (-9)x(-7)
= - 45/63
= - 5/7

1. (+2)+(+1)+(-5)
=2+1-5
= -2

2. (+5)+(-8)+(+3)
=5-8+3
= 0

3. (-1)+(-2)+(-4)
=-1-2-4
= -7

4. (+9)+(-3)+(-7)
=9-3-7
= -1

5. (+8)-(+7)-(-5)
=8-7+5
= 6

6. (-6)-(-9)-(+4)
=-6+9-4
= -7

7. -16+(+23)+(-2)
=-16+23-2
= 5

8. 5-(-14)-(+30)
=5+14-30
= -11

9. -3-(-19.3)+0.5
=-3+19.3+0.5
= 16.8

10. (-7.2)-(+2.3)+(-5)
=-7.2-2.3-5
= -14.5
--------------------------------
1. (-81) / (-27)
= 3

2. (+225) / (+5)
= 45

3. (-231) / (+11)
= -21

4. (-28) / (+2) / (+7)
=-14 / 7
= -2

5. (+42) / (+3) / (-21)
=14 /( -21)
= -2/3

6. (+36) / (-2)(+6)
=36/(-12)
= -3

7. (+4)x(-6) / (-12)
=(-24) / (-12)
= 2

8. (-7)x(+3) / (-21)
=(-21) / (-21)
= 1

9. (-45) / (-9)x(-7)
=(-45) / 63
= - 5/7

正正得正 负负得正 正负得负 负正得正

记得以上十六个字你就没问题了 可以帮你做一条 其他你自己试试

1.
(+2)+(+1)+(-5)
2 +1 (+(1)正正得正) -5 (+(-5)正负得负)
2+1-5
-2