Bài 1:
a) -5/18 + 5/9 - 11/36
= -5/18 + (5/9 - 11/36)
= -5/18 + (20/36 - 11/36)
= -5/18 + 9/36
= -10/36 + 9/36
= -1/36
Vậy -5/18 + 5/9 - 11/36 = -1/36
b) (-7/11).11/19 + (-7/11).8/19 - 4/11
= (-7/11).(11/19 + 8/19) - 4/11
= (-7/11).19/19 - 4/11
= (-7/11).1 - 4/11
= (-7/11) - 4/11
= -11/11
= -1
Vậy (-7/11).11/19 + (-7/11).8/19 - 4/11 = -1
c) 2/7 + 5/7.|3/5 - 0,25|. (-2)² + 35%
= 2/7 + 5/7.|3/5 - 1/4|. 4 + 7/20
= 2/7 + 5/7.|7/20|.4 + 7/20
= 2/7 + 5/7.7/20.4 + 7/20
= 2/7 + 7/20.(5/7.4 + 1)
= 2/7 + 7/20.(20/7 + 1)
= 2/7 + 7/20.27/7
= 2/7 + 27/20
= 229/140
Vậy 2/7 + 5/7.|3/5 - 0,25|. (-2)² + 35% = 229/140