Precedence Issue
lWe must ensure that the derivation tree for a+b*c looks like this: and not this:
+
c
a
b
*
*
a
c
b
+
A
M + A
V  *  M
V
V
b
c
a
M
A  *   M
V + A
V
V
b
c
a
M
(loose)
(tight)