15. A scuba diving instructor takes a group of students to a depth of 54.96 feet. Then they ascend 22:33 feet to see some fish. Where are the fish in relation to the sumace? 15. Model with Math Write an addition expression that is represented by the Sumber line. 2 17. The roots of a plant reach down - inches below ground. How many inches is the plant above the ground? 18. Higher Order Thinking Simplify the expression (-13.2) – 8.1. bHow are (-13.2) – 8.1 and 13.2 - (-8.1) related? Explain without computing. 12 in 3 in c. Using a property of operations, what can you say about the sum of the two expressions?