初一代數!!正負數!

1.)求+7,-9,+23,-75的和:

(+7)+(-9)+(+23)+(-75)

=-54

2.)求+4份1,-1又3份1,31又5份3,-28又6份1的和:

(+1/4)+(-4/3)+(158/5)+(-167/6)

=30+31/60+(-167/6)

=2+41/60

求+3ab,-4份1ab,+22又5份1ab,-ab的和:

2010-09-28 20:03:18 補充：
(+3ab)+(1ab/-4)+(+22+1ab/5)+(-ab)

2010-09-28 20:04:03 補充：
=3ab+1ab/-4+22+1ab/5-ab

2010-09-28 20:07:17 補充：
=+22+3ab-ab+1ab/-4+1ab/5

=22+2ab+{[5ab/-20]+[4ab/20]}

=22+2ab+ab

=22+3ab

1.
+7+(-9)+(+23)+(-75)
=7-9+23-75
=(-2)+23-75
=21-75
= -54

2010-09-28 18:40:50 補充：
+1/4)+(-4/3)+(158/5)+(-169/6)
=+1/4-4/3+158/5-169/6
=+2/20/7

=2_7_
20

2010-09-28 18:42:08 補充：
q3 what your ab is
i don't know sorry

和~所以將佢地加埋
+7,-9,+23,-75
=(+7)+(-9)+(+23)+(-75)
=+7-9+23-75←折括號
=-54

求和~所以都係加.
(+1/4)+(-4/3)+(158/5)+(-169/6)
=+1/4-4/3+158/5-169/6←折括號
=+2又20份之7

第一題係
-54
第二題係
2又20份之7(唔肯定,但係應該岩)
第三題其實我唔明你個AB講咩,SORRY!
希望個兩題幫到你=)