Answer
640KB = 655,360 cells
512MB = 536,870,912 cells
2GB = 2,147,483,648 cells
Work Step by Step
Since each cell have one byte data, we have
Number of cells = Number of bytes
640KB=640 X 1024 = 655,360 bytes
512MB=512 X 1024 X 1024= 536,870,912 bytes
2GB=2 X 1024 X 1024 X 1024= 2,147,483,648 bytes
