Question

Doug dives from a platform that is 5 meters above water. His dive takes him 2.6 meters below the surface of the water. How far does Doug's dive take him?

Answer 1

Because the 2.6 is below the warter you can write it as -2.6 because it is lower than the 0 point.

Then you can take the -2.6 away from the 5 and rewrite the equation and solve:
5 - -2.6 = 5+2.6 = 7.6

The answer is the dive took him 7.6m down.
Hope this helps! :)