Discussion 2: Models for Addition and Subtraction 8282 unread replies.8282 replies. For the problems below, (a) classify the word problem (based on the tables from page 21 of the coursepack), (b) create a separate drawing for each problem based on the conceptual model that it relates to, and (c) describe how the drawing can be used to find/show the solution. Andria poured herself 12 ounces of milk. She drank 7 ounces. How much milk is left in her glass? Byron is training for a marathon. Today he needs to run 12 miles. He has run 7 miles already. How much farther does Byron need to run today to reach his training goal? Mari is 12 years old and her brother Liu 7 years old. How much older is Mari than Liu