--聽日交-- 各位知識朋友 , 入黎幫我手 ar !!! ( 數學F.1 ) (3)

1.(a)0-［(-5)-(-7)］
=0- [-5+7]
=0- (+2)
=0-2
= -2

(b)(-7)-(-4)+(-3)-(+5)
= -7+4-3-5
= -3-3-5
= -6-5
= -11

(c)4-9+(-9)-(-4)
=4-9-9+4
= -5-9+4
= -14+4
= -10

(d)(-3)-9+(-4)-7-(+6)
= -3-9-4-7-6
= -12-4-7-6
= -16-7-6
= -23-6
= -29

(e)7.4-(-3.6)+(+1.8)
=7.4+3.6+1.8
=11+1.8
=12.8

(f)-［2+(5∕6 - 4∕3)］
= -［2+(5∕6 - 8∕6)］
= - ［2+( - 3 / 6)]
= - (2- 3/ 6)
= - ( 1 and 6/6 - 3/6)
= - ( 1 and 1/2)
= - 1 and 1/2

(g)-12+［10-(-8)-25］-(2-15+4)
= -12+ (10+8-25)- 2+15-4
= -12+10+8-25-2+15-4
= -2+8-25-2+15-4
= 6-25-2+15-4
= -19-2+15-4
= -21 +15-4
= -6-4
= -10

(h)-3-｛-3-［-3-(-3)］｝
= -3-[ -3- (-3 +3) ]
= -3- (-3- 0)
= -3- (-3)
= -3+3
= 0

自己試下啦...記住!!負負得正!!