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1) 2/5 . 3/8 + 5/8 . 2/5
= 2/5 . ( 3/8+5/8)
= 2/5 . 1
= 2/5
2) 2/3 . 5/2 - 3/4 . 2/3
= 2/3 . (5/2-3/4)
= 2/3 . (10/4-3/4)
= 2/3 . 7/4
= 7/6
3) 5/7 . 19/23 - 12/23 . 5/7
= 5/7 . (19/23 - 12/23)
= 5/7 . 7/23
= 5/23
3)
4) 7/2 . 11/6 - 7/2 . 5/6
= 7/2 . (11/6 - 5/6)
= 7/2 . 1
= 7/2
5) 11/9 . 3/4 - 2/9 . 3/4
= 3/4 . (11/9 - 2/9)
= 3/4 . 1
= 3/4
6) 3/7 . 13/5 + 3/7 . 8/5
= 3/7 . (13/5 + 8/5)
= 3/7 . 21/5
= 9/5
7) 2/7 . 8/19 + 5/7 . 8/19
= 8/19 . ( 2/7 + 5/7)
= 8/19 . 1
= 8/19
8) 23/15 . 3/8 - 17/15 . 3/8
= 3/8 . ( 23/15 - 17/15)
= 3/8 . 2/5
= 3/20
9) 3/2 . 5/3 - 7/6 . 3/2
= 3/2 . (5/3 - 7/6)
= 3/2 . 1/2
= 3/4
10) 7/15 . 16/13 + 7/15 . (- 3/13)
= 7/15 . (16/13 - 3/13)
= 7/15 . 1
= 7/15
11) -23/7 . 3/10 + 13/7 . 3/10
= 3/10 . (-23/7 + 13/7)
= 3/10 . (- 10/7)
= -3/7
12) -11/8 . 19/3 + 19/3 . -5/8
= 19/3 . ( -11/8 - 5/8)
= 19/3 . (-2)
= -38/3
13) -2/3 . 3/11 + (-16/9) . 3/11
= 3/11 . (-2/3 - 16/9)
= 3/11 . (-22/9)
= -2/3
14) -5/9 . 3/11 + (-13/18) . 3/11
= 3/11 . (-5/9 - 13/18)
= 3/11 . (-23/9)
= -23/33
15) 2/13 . (-5/3) + 11/13 . (-5/3)
= -5/3 . ( 2/13 + 11/13)
= -5/3 . 1
= -5/3
16) -9/13 . 5/17 + (-17/13) . 5/17
= (-9/13 - 17/13) . 5/17
= -2 . 5/17
= -10/17
17) 7/15 . (-4/9) + (-5/9) . 7/15
= 7/15 . (-4/9 - 5/9)
= 7/15 . (-1)
= -7/15
18) 3/8 . (-23/14) - 3/8 . (-9/14)
= 3/8 . (-23/14 + 9 /14)
= 3/8 . ( -1)
= -3/8