中一數學(四則運算)

首先，你要明白一個道理：
x-(y-z)=x-y+z
x-(y+z)=x-y-z
1. 4–(6–12)=
=4-6+12
=10

2. (5–13)–17=
=5-13-17
=-25

3. 10–(9+12)=
=10-9-12
=-11

4. 0–(–16)+(–8)=
=0+16-8
=8

5. –7–(–4)+(–3)=
=-7+4-3
=-6

6. 7–(+9)+(–5)=
=7-9-5
=-7

7.(+10)+(–5)–(–10)=
=10-5+10
=15

8.(+8)–(–7)+(–9)=
=8+7-9
=6

9.(–5)+(–8)–(+3)=
=-5-8-3
=-16

10.(–15)+(+35)+(–10)=
=-15+35-10
=10

11.(5–7)–(2–6)=
=-2-2+6
=-2
即是負負得正-(-)= +
正負得負+(-)= -
負正得負-(+)= -
正正得正+(+)= +


2009-03-18 18:40:26 補充：
唔好意思

等11條的答案是2

快覽：
1.10
2.-25
3.-11
4.8
5.-6
6.-7
7.15
8.6
9.-16
10.10
11.2


詳細：
1.4-(6-12)
=4-6+12
=10

2.(5-13)-17
=-8-17
=-25

3.10-(9+12)
=10-9-12
=-11

4.0-(-16)+(-8)
=0+16-8
=8

5.-7-(-4)+(-3)
=-7+4-3
=-3-3
=-6

6.7-(+9)+(-5)
=7-9-5
=-7

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

8.(+8)-(-7)+(-9)
=8+7-9
=15-9
=6

9.(-5)+(-8)-(+3)
=-5-8-3
=-16

10.(-15)+(+35)+(-10)
=-15+35-10
=20-10
=10

11.(5-7)-(2-6)
=5-7-2+6
=-2-2+6
=-4+6
=2

1. 4–(6–12)=10

2. (5–13)–17=-25

3. 10–(9+12)=-11

4. 0–(–16)+(–8)=8

5. –7–(–4)+(–3)=-6

6. 7–(+9)+(–5)=-7

7.(+10)+(–5)–(–10)=15

8.(+8)–(–7)+(–9)=6

9.(–5)+(–8)–(+3)=-16

10.(–15)+(+35)+(–10)=10

11.(5–7)–(2–6)=2

1. 10
2. -25
3. -11
4. 8
5. -6
6. -7
7. 15
8. 6
9. -16
10. 10
11. 2

1. 10
2. -25
3. -11
4. 8
5. -6
6. -7
7. 15
8. 6
9. -16
10. 10
11. 2

1. 4–(6–12)=?
=10

2. (5–13)–17=?
=–25

3. 10–(9+12)=?
=–11

4. 0–(–16)+(–8)=?
=8

5. –7–(–4)+(–3)=?
=–6

6. 7–(+9)+(–5)=?
=–5

7.(+10)+(–5)–(–10)=?
=15

8.(+8)–(–7)+(–9)=?
=6

9.(–5)+(–8)–(+3)=?
=–16

10.(–15)+(+35)+(–10)=?
=10

11.(5–7)–(2–6)=?
=2



I hope I can help you

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