Java generic type parameter not within its bound

Preparing for OCPJP 6 exam (that's why I'm using Java 1.6 compiler) I've noticed something unclear to me about Java Generics. Consider the following code:

class A<K extends Number> {

    public <V> V useMe1(A<? super V> a) { // OK
        return null;
    }

    public <V> V useMe2(A<? extends V> a) { // OK
        return null;
    } 

    public <V> V useMe3(A<V> a) { // ERROR, but why, since 2 above were ok
        return null;
    } 

}

When I try to compile the code (with 1.6 compiler), I get the error:

type parameter V is not within its bound

Despite unusability of the code above, I'm wondering why does compiler think that types <? super V> and <? extends V> are matching the class type bound but <V> is not (since V is matching those both bounds).

I'm not going to modify that code, I want to understand it. The code is taken from sample OCPJP 6 exam question asking "Which line will compile?"