Sameer woke up one morning and saw frost on the windows. It was -7°C outside. Later in the day, the frost melted. At 3 p. m. it was 2°C outside. Which expression represents the difference between the two temperatures?

Ms.lopez has 4 liters of chemicals that she is going to pour into beakers. each beaker will have 1/4 of a liter of chemicals, how many beakers can ms.lopez fill? draw a model to support your work. (it's ok if you dont)