A range is a group of cells. A range has two basic characteristics. All cells in a range are adjacent. The outline of a block is rectangular, since it may be defined by expanding the pointer. Blocks are important because many Excel functions and commands use block to simplify entry.
Some examples are copy, move, format, etc.
Defining a block involves specifying the upper left and lower right corners of the range by highlighting the area using your mouse. You highlight by dragging the pointer over the selected cells with the left mouse button pressed down. It gives the user the opportunity to copy or move contents of a cell to another cell without have to retype the information. The information can contain text as well as a formula or function. One of the most outstanding things about this is the ability to copy a formula or function and the flexibility in Excel as it easily changes the cell labels.