Final answer:
Sally ordered 3 toppings on her pizza. The total cost for the additional toppings was calculated by subtracting the base price of the pizza from the total bill and dividing the remainder by the price per topping.
Step-by-step explanation:
To find out how many toppings Sally ordered, we need to subtract the cost of the plain cheese pizza from the total bill and then divide the difference by the cost of each additional topping.
We are given that a large cheese pizza costs $7.00 and each additional topping costs $2.00. Sally's total bill was $13.00.
First, subtract the cost of the cheese pizza from the total bill: $13.00 - $7.00 = $6.00.
Then divide the remaining amount by the cost of each topping: $6.00 / $2.00 = 3.
Therefore, Sally ordered 3 toppings.