(1) In calculating for the purposes of Part III of this Constitution any

20. (1) In calculating for the purposes of Part III of this Constitution any residence in the Federation— (a) a period of absence from the Federation of less than six months; (b) a period of absence from the Federation for the purposes of education of such kind, in such country and for such time as may from time to time be either generally or specially approved by the Minister; (c) a period of absence from the Federation for reasons of health; (d) a period of absence from the Federation on duty in the service of the Federation or of any State, where such period is not inconsistent with the essential continuity of such residence; and (e) a period of absence from the Federation for any other cause prescribed generally or specially by the Minister, shall be treated as residence in the Federation. (2) In calculating for the purposes of Part III of this Constitution any residence in the Federation— (a) a period during which a person was not lawfully resident in the Federation; (b) a period spent as an inmate of any prison or as a person detained in lawful custody in any other place, other than a mental hospital, under the provisions of any written law of the Federation; and (c) a period during which a person is allowed to remain temporarily in the Federation under the authority of any pass issued or exemption order made under the provisions of any written law of the Federation relating to immigration, shall not, except in the case of any period referred to in paragraph (c), with the consent of the Minister, be treated as residence in the Federation. (3) For the purposes of Part III of this Constitution a person shall be deemed to be resident in the Federation on a particular day if he had been resident in the Federation before that day and that day is included in any period of absence referred to in subsection (1).