Tomas works as an underwater photographer. He starts at a position that is 15 feet below sea level. He rises 9 feet, then descends 12 feet to take a photo of a coral reef. Write and evaluate an expression to find his position relative to sea level when he took the photo.

The temperature on a winter night was -23 °F. The temperature rose by 5 °F when the sun came up. When the sun set again, the temperature dropped by 7 °F. Write and evaluate an expression to find the temperature after the sun set.

Jose earned 50 points in a video game. He lost 40 points, earned 87 points, then lost 30 more points. Write and evaluate an expression to find his final score in the video game.

-6 + 15 + 15 =

9 - 4 - 17 =

50 - 42 + 10 =

6 + 13 + 7 - 5 =

65 + 43 - 11 =

-35 - 14 + 45 + 31 =

-12 + 6 - 4 or -34 - 3 + 39

21 - 3 + 8 or -14 + 31 - 6

Explain how you can find the value of the expression -5 + 12 + 10 - 7.