What is the easiest way to add and subtract negative numbers?

Ill mark the brainliest if you me with the these three questions 7,8,9

Helena lost her marbles. but then she found them and put them in 44 bags with mm marbles in each bag. she had 33 marbles left over that didn't fit in the bags.

The stem-and-leaf plot shows the heights in centimeters of teddy bear sunflowers grown in two different types of soil. soil a soil b 5 9 5 2 1 1 6 3 9 5 1 0 7 0 2 3 6 7 8 2 1 8 3 0 9 key: 9|6 means 69 key: 5|8 means 58 calculate the mean of each data set. calculate the mean absolute deviation (mad) of each data set. which set is more variable? how do you know?