I NEED help :( PLZ

The table shows the webster family’s monthly expenses for the first three months of the year. they are $2,687.44, $2,613.09, and $2,808.64. what is the average monthly expenditure for all expenses?

Ateacher wanted to buy a chair, a bookshelf, two tables and a desk. she spent $900 for all five items and the chair and the desk combined 70% of her total. if the bookshelf cost $50, how much did each of the tables cost?

47: 4 aisha changed 1.45 + 2.38 to 1.5 + 2.4 in order to estimate the sum. what estimation method did she use?