負數與正數(加、減、乘、除)

1)1+(2-3)-(-4-5)
= 1+2-3+4+5
=4+5
=9

2)1+2x(-3)-(4-5)
=1-6-4+5
=-4

3)15-3(8-4)-2(6-7)
=15-24+12-12+14
=5

4)5+(7-5)(-3)-(4)(-5)
=5-21+15+20
=19

5)5-(7-5)(-3)+(-4)(-5)
=5+21-15+20
= 31


6)2-(5-3x4)-(-7)
=2-5+12+7
=16


7)2-5(4x3-9)+(-7)(3)
=2-60+45-21
=-34

1)1+(2-3)-(-4-5)
=1+(-1)-(-9)
=1-1+9
=9

2)1+2x(-3)-(4-5)
=1-6x-(-1)
=1-6x+1
=2-6x

3)15-3(8-4)-2(6-7)
=15-3(4)-2(-1)
=15-12+2
=5

4)5+(7-5)(-3)-(4)(-5)
=5+(2)(-3)-(-20)
=5-6+20
=19

5)5-(7-5)(-3)+(-4)(-5)
=5-(2)(-3)+(-20)
=5+6-20
=-9

6)2-(5-3x4)-(-7)
=2-(-7)+7
=9+7
=16

7)2-5(4x3-9)+(-7)(3)
=2-15+(-21)
=-13-21
=-34

1)1+(2-3)-(-4-5)
=1+(-1)-(-9)
=1-1+9
=0+9
=+9

2)1+2x(-3)-(4-5)
=1+(-6)-(-1)
=1-6+1
=-5+1
=-4

3)15-3(8-4)-2(6-7)
=15-3(+4)-2(-1)
=15-(+12)-(-2)
=15-12+2
=+3+2
=+5

4)5+(7-5)(-3)-(4)(-5)
=5+(+2)(-3)-(+20)
=5+(-6)-(+20)
=5-6-20
=-1-20
=-21

5)5-(7-5)(-3)+(-4)(-5)
=5-(+2)(-3)+(+20)
=5-(-6)+(+20)
=5+6+20
=+11+20
=+31

6)2-(5-3x4)-(-7)
=2-(5-12)-(-7)
=2-(-7)-(-7)
=2+7+7
=9+7
=+16

7)2-5(4x3-9)+(-7)(3)
=2-5(12-9)+(-21)
=2-5(+3)+(-21)
=2-(+15)+(-21)
=2-15-21
=-13-21
=-34

計完了!! Is that F.1 Maths??

2008-09-23 21:43:07 補充：
I hope I can help u!!

1)1+(2-3)-(-4-5)
=1+2-3+4+5
=9
=

2)1+2x(-3)-(4-5)
=1-6+4+5
=4
=

3)15-3(8-4)-2(6-7)
=15-24+12-12+14
=5
=

4)5+(7-5)(-3)-(4)(-5)
=5-21+15+20
=19
=

5)5-(7-5)(-3)+(-4)(-5)
=5-21-15+20
= -11
=

6)2-(5-3x4)-(-7)
=2-5+12+7
=16
=

7)2-5(4x3-9)+(-7)(3)
=2-60+45-21
=-34
=

唔知對唔對的，因為我是用心算~(我心算唔好的=.=)懶得用計算機計

1. 9
2. -4
3.唔識- -
4.唔識- -
5.唔識- -
6. 1
7.唔識
*唔知岩唔岩架!!

1)1+(2-3)-(-4-5)
=1+(-1)-(-9)
=1-1+9
=9

2)1+2x(-3)-(4-5)
=1-6x-(-1)
=1-6x+1
=2-6x

3)15-3(8-4)-2(6-7)
=15-3(4)-2(-1)
=15-12+2
=5

4)5+(7-5)(-3)-(4)(-5)
=5+(2)(-3)-(-20)
=5-6+20
=19

5)5-(7-5)(-3)+(-4)(-5)
=5-(2)(-3)+(-20)
=5+6-20
=-9

6)2-(5-3x4)-(-7)
=2-(-7)+7
=9+7
=16

7)2-5(4x3-9)+(-7)(3)
=2-15+(-21)
=-13-21
=-34