4- There are two 2 (summation) block ,what is the difference between them , and what is the role of each one ?

Assume your company buys a parcel of land containing 283.5 acres. One-fourth of the land must be used for streets, and each homesite is to contain 3/7 of an acre. How many homesites will there be?

The locations of a spider (S) and its prey (P) are shown on the box below. The spider is on the front of the box, 1" from the bottom and 1" from the left side. The prey is on the back of the box 1" from the top and 1" from the right. The front, top and bottom sides of the box are 2" X 3". The left and right sides of the box are each 2" X 2". Find the shortest distance the spider must travel to get its prey. Find this length.