Add and Subtract Rational Numbers Practice Test

A weather station records hourly temperature changes from noon: $$+3.5°F$$, $$-2.8°F$$, $$-4.1°F$$, $$+1.9°F$$, $$-5.2°F$$. To find the net temperature change, a meteorologist uses the expression $$3.5 + (-2.8 - 4.1 - 5.2) + 1.9$$. What is the error in this regrouping?

During a card game, Alex's score changes are: $$+24$$, $$-18$$, $$+15$$, $$-31$$, $$+8$$. He wants to calculate his total score change by grouping positive and negative values: $$(24 + 15 + 8) + (-18 + (-31))$$. What properties of operations justify this regrouping, and what is the total change?