2. \( \begin{aligned} \frac{a+b}{2} \div \frac{3 a+3 b}{4} & =\square \\ & =\square \\ & =\square\end{aligned} \)

Let’s break this down step by step! First, you'll notice that dividing by a fraction is the same as multiplying by its reciprocal. So, we can rewrite the expression: \[ \frac{a+b}{2} \div \frac{3a+3b}{4} = \frac{a+b}{2} \times \frac{4}{3a + 3b} \] Now, simplify \(3a + 3b\) to \(3(a + b)\). Plugging that in gives us: \[ \frac{a+b}{2} \times \frac{4}{3(a+b)} \] Next, you can cancel \(a+b\) from the numerator and denominator (assuming \(a + b \neq 0\)): \[ = \frac{4}{2 \cdot 3} = \frac{4}{6} = \frac{2}{3} \] So, the final answer is: \[ \frac{a+b}{2} \div \frac{3a+3b}{4} = \frac{2}{3} \] Now you have all the squares filled in!