a 9/2+1/18:-2/33
=9/2+1/18*(-33/2)
=9/2+(-33/36)
=162/36-33/36
=129/36
=43/12
b 3/10+13/10:-1/10
=3/10+13/10*(-10)
=3/10-13
=3/10-130/10
=-127/10
c 1/3+16/15:-4/17
1/3+16/15*(-17/4)
=1/3+4/15*(-17)
=1/3-68/15
=5/15-68/15
=-63/15
=-21/5
d 5/2*(3/4-9/28)
=5/2*(21/28-9/28)
=5/2*12/28
=5*6/28
=30/28
=15/14
e -5/14-3/7*(-7/2)
=-5/14+3/2
=-5/14+21/14
=16/14
=8/7
f -13/8:1/39*11/13
-13/8*39/1*11/13
=-1/8*3/1*11/13
=-33/104
