Evaluate each expression below. Click on "Undefined" as needed. \[ \begin{array}{r} 0 \div 4=\square \\ \frac{0}{6}=\square \end{array} \] (a) Undetined

Step 1 ：The question is asking to evaluate two expressions: 0 divided by 4 and 0 divided by 6. In mathematics, any number divided by zero is undefined, but zero divided by any number is always zero. So, we can directly calculate these expressions.

Step 2 ：The results of the expressions are: \[\begin{array}{r} 0 \div 4= \boxed{0} \\ \frac{0}{6}= \boxed{0} \end{array}\]