✔ 最佳答案
你好～～～
以下都是敝人的一些愚見而已，如有錯誤請多多指教！
1) 2+[3分之2-(-7+4)]
= 2 + [2/3 - (-3)]
= 2 + (2/3 + 3)
= 5 + 2/3
= 5 又 2/3
2) -12+[10-(-8又4分之3)-25]-(2-6又4分之1)
= -12 + (10 + 35/4 - 25) - (2 - 25/4)
= -12 + (-25/4) - 2 + 25/4
= -12 - 2
= -14
3) A submarine moves 50 m up from 100 m below the sea level,and then moves 80 m down.Express the final location of the submarine in a directed number.
Sol: Original Distance = -100m
50m up = +50m
80m down = -80m
-100 + 50 - 80 m
= -130m
4) One day,Kevin forgot to bring his wallet.In the morning,he borrowed $12 from Vivian for breakfast.In the afternoon,he borrowed$22 from her again for lunch.If Kevin returnes$20 to Vivian the next day,how much was he still owing Vivian?
Sol: The first borrowing = -$12
The second borrowing = -$22
The return = +$20
$(-12 - 22 + 20) = $(-34 + 20) = -$14
5a) (2)(+6)
= 2 x 6
= 12
5b) (+10)(+15)
= 10 x 15
= 150
5c) (+7)(-9)
= 7 x (-9)
= -63
5d) (-5)(+20)
= 20 x (-5)
= -100
5E) (-8)(-6)
= (-1 x 8)(-1 x 6)
= (-1)(-1) x (8 x 6)
= 1 x 48
= 48
5f) (-3)(-12)
= (-1)^2 x (3 x 12)
= 1 x 36
= 36
6a) (+35)/(+5)
= 35 / 5
= 7
6b) (+48)/(-2)
= 48 / (-2)
= -24
6c) (-32)/(+8)
= -4
6d)(-24)/(-3)
= (-1)(24) / (-1)(3)
= 8
6e)-9分之+126
= (-9) / (+126)
= (-1) / 14
= -(1 / 14)
6f) -11分之-242
= (-11) / (-242)
= (-1)(11) / (-1)(242)
= 1 / 22
要記得︰
(-)(+) = -
(+)(-) = -
(+)(+) = +
(-)(-) = +
(+) / (-) = -
(-) / (+) = -
(+) / (+) = +
(-) / (-) = +
希望可以幫到你～～～～～
2010-09-14 20:17:15 補充：
這位抄襲者真醒目，幸好他是小學級三級，才能轉顏色呢～～～～～
