[tex]13a - 5a + 2\frac{1}{3}a - 4a+\frac{1}{2}a =4a + 2\frac{2}{6}a + \frac{3}{6}a = 4a + 2a + \frac{2}{6}a + \frac{3}{6}a = 6\frac{5}{6}a[/tex]
[tex]2xy - 3xy + 2\frac{1}{5}xy + 4\frac{3}{5}xy + 6\frac{1}{5}xy = -xy + 12\frac{5}{5}xy = -xy + 13xy = 12xy[/tex]
