1. State the problem: For Greta's birthday party, her parents ordered $6$ pizzas and they cut each pizza into sixths, so how many pieces will there be? 2. Formula used: The number of pieces equals the number of pizzas times the number of slices per pizza. Formula: $$\text{pieces} = \text{pizzas} \times \text{slices per pizza}$$ 3. Apply the values: Replace with the given numbers. $$\text{pieces} = 6 \times 6$$ Compute: $$= 36$$ 4. Explanation: Each pizza is cut into $6$ slices and there are $6$ pizzas, so there are $6$ groups of $6$ slices which makes $36$ slices in total. 5. Model choice and final answer: The correct model is the second image (all slices shown on all $6$ pizzas). The final answer is $36$ pieces.