Suppose that lisa walks her dog around the block for a little exercise. the block is 1 mile around. if she walks around the block once, what is her displacement? what is her distance?

Displacement is defined as the net distance traveled through the entire trip. That is to say, if you compared where you are at the end of the walk to where you were at the start, the displacement is the distance between those two points.

Distance doesn't compare the two end points. It just counts the total distance you've walked throughout your trip.

Lisa walks once around the block. She starts and ends at the same place. Her displacement is therefore 0 m.

But she has walked 1 mile throughout the trip. Her distance walked is therefore 1 mile.