`a)2/7+(-3)/8+11/7+1/3+1/7+5/(-8)`
`=2/7+(-3)/8+11/7+1/3+1/7+(-5)/8`
`=(2/7+11/7+1/7)+((-3)/8+(-5)/8)+1/3`
`=14/7+(-8)/8+1/3`
`=2+(-1)+1/3`
`=1+1/3`
`=3/3+1/3`
`=4/3`
`b)(-3)/8+12/25+5/(-8)+2/(-5)+13/25`
`=(-3)/8+12/25+(-5)/8+(-2)/5+13/25`
`=((-3)/8+(-5)/8)+(12/25+13/25)+(-2)/5`
`=(-8)/8+25/25+(-2)/5`
`=(-1)+1+(-2)/5`
`=0+(-2)/5`
`=(-2)/5`
`c)7/8+1/8 . 3/8+1/8 . 5/8`
`=7/8+1/8 .(3/8+5/8)`
`=7/8+1/8 . 8/8`
`=7/8+1/8 . 1`
`=7/8+1/8`
`=8/8`
`=1`
`d)(-5)/6 . 4/19+(-7)/12 . 4/19-40/57`
`=4/19 .((-5)/6+(-7)/12)-40/57`
`=4/19 .((-10)/12+(-7)/12)-40/57`
`=4/19 . (-17)/12-40/57`
`=(-17)/57-40/57`
`=(-17)/57+(-40)/57`
`=(-57)/57`
`=-1`
`e)4/9:(-1/7)+6(5)/9:(-1/7)`
`=4/9 .(-7)+59/9 .(-7)`
`=(-7).(4/9+59/9)`
`=(-7). 63/9`
`=(-7).7`
`=-49`
`f)5(2)/7 . 8/11+5(2)/7 . 5/11-5(2)/7 . 2/11`
`=37/7 . 8/11+37/7 . 5/11-37/7 . 2/11`
`=37/7 .(8/11+5/11-2/11)`
`=37/7 . 11/11`
`=37/7 .1`
`=37/7`
`g)3(3)/5+(-3)/5 . 4/7+(-3)/5 . 3/7`
`=18/5+(-3)/5 .(4/7+3/7)`
`=18/5+(-3)/5 . 7/7`
`=18/5+(-3)/5 .1`
`=18/5+(-3)/5`
`=15/5`
`=3`
`k)12/19:7/5-(-7)/19:7/5-1(5)/7`
`=12/19 . 5/7+7/19 . 5/7-12/7`
`=5/7 .(12/19+7/19)-12/7`
`=5/7 . 19/19-12/7`
`=5/7 .1-12/7`
`=5/7-12/7`
`=(-7)/7`
`=-1`