Ibn ‘Abbâs and Abû Hurayrah – Allâh be pleased with them – said, “There is no harm in making up [fasts of] Ramadân separately from one another.”
‘Abd Al-Razzâq, Al-Musannaf 4:243; Ibn Abî Shaybah, Al-Musannaf article 9114; Al-Dâraqutnî, Al-Sunan 2:193.
Abû ‘Ubaydah b. Al-Jarrâh – Allâh be pleased with him – said, when asked about making up missed fasts of Ramadân separately, “Allâh did not legislate upon you the breaking of the fast, and then cause hardship on you when making it up, so count the days [you excusably missed] and fast them as you wish.”
Ibn Abî Shaybah, op. cit. article 9133.
Anas b. Mâlik – Allâh be pleased with him – said, “If you wish, make up [missed fasts of] Ramadân consecutively, or if you wish, make them up separately.”
Ibid. article 9115.