The number of cells that are included in the range A1:B3 is 6.
The grid-like boxes in an Excel spreadsheet like this one are called cells. On a worksheet, each cell is identifiable by its reference, the column letter, and the row number that crosses the cell's position.
This cell is cell D5 because it is in column D and row 5. In a cell reference, the column is always referenced first. A column and a row's intersection form a rectangular space known as a cell.
The Cell Name (or Reference, which is discovered by adding the Column Letter and the Row Number), is used to identify cells. It is simpler to click the initial cell while depressing the Shift key, then click the last cell in the range to select a greater range.
Therefore, there are 6 cells total that make up the range A1:B3.
To learn more about cells in Excel, refer to the link: