Abstract: A foldable calculator comprising: (i) a main body having an upper cover with a rectangular recess on the outer surface of the upper cover, a lower cover; and a hinge joining the upper cover and the lower cover together, (ii) a display screen, (iii) a keyboard having a first key set (frequently used keys) with relatively large key pressing areas and a second key set (infrequently used keys) with relatively smaller key pressing areas, and (iv) a retractable support member, wherein the upper cover is openable at an angle from the lower cover suitable for a user to view the display screen when the retractable support member is open, and the retractable support member is retractable into the rectangular recess on the outer surface of the upper cover when the retractable support member is not in use.