a) -2 + 4/3 - (-4/5)
-2 * 3 / 1 * 3 + 4/3 - (-4/5)
-6/3 + 4/3 - (-4*3/5*3)
-6*5/3*5 + 4*5/3*5 - (-12/15)
-30/15 + 20/15 + 12/15
2/15
b) -2 + (-5/4) - (-29/10)
-2*20/1*20 + (-5*5/4*5) - (-29*2/10*2)
-40/20 + (-25/20) - (-58/20)
-40/20 - 25/20 + 58/20
- 65/20 + 58/20
-7/20
