Bài 1:
a) 2 - 3/3/4 : (5/8 - 1/6)
= 2 - 15/4 : (30/48 - 8/48)
= 2 - 15/4 : 11/24
= 2 - 15/4 . 24/11
= 2 - 15/1 . 6/11
= 2 - 90/11
= -68/11
b) (1 - 1/5 - 2/3) : (2/2/5 + 1/3)
= (1/1 - 1/5 - 2/3) : (12/5 + 1/3)
= (15/15 - 3/15 - 10/15) : (36/15 + 5/15)
= 2/15 : 41/15
= 2/15 . 15/41
= 2/41
c) 8/13 + -19/41 + 5/13 + -9/15 + -22/41
= (8/13 + 5/ 13) + (-19/41 +-22/41) + -9/15
= 1 + (-1) + -9/41
= -9/41
3b:
Ta có:
1/101 > 1/200
1/102 > 1/200
1/103 > 1/200
...
1/199 > 1/200
1/200 = 1/200
=> 1/101 + 1/102 + 1/103 + ... + 1/200 > 1/200 + 1/200 + 1/200 + ... + 1/200
=> 1/101 + 1/102 + 1/103 + ... + 1/200 > 1/200 . 100 = 1/2
Vậy biểu thức đã cho > 1/2
