Can anyone please help i would really appreciate it
i don't get this at all

Which addition property is being illustrated below? (type commutative or associative) (6 + 7) + 1 = 6 + (7 + 1)

Angel entered a triathlon (a three-part race). he swam 1 mile, rode his bike 30 miles, and ran 10 miles. how far did he go altogether? a. 11 miles b. 123 miles c. 41 miles d. 40 miles

Haruka hiked several kilometers in the morning. she hiked only 66 kilometers in the afternoon, which was 25% less than she had hiked in the morning. how many kilometers did haruka hike in all?