Countidaya sanduna, Sanya na 100
E51.0124-7: sandunan roba, Dia.0.2 * 7cm, 5 Launi, 100 inji mai kwakwalwa / Bag
E51.0124-10: sandunan roba, Tsawon 10cm, Launi 5, 100 inji mai kwakwalwa / Bag
Countidaya (ƙidaya) kuma ana san shi da ƙidaya. Ofaya daga cikin mahimman ka'idojin lissafi. Hanyar tantance abubuwa da yawa. Idan ana kirgawa, galibi mutum yana nufin kowane abu, yana ƙidaya ɗaya bayan ɗaya, kuma yana sake karanta lambobi 1, 2, 3, 4, 5, da sauransu a cikin lambar lamba mai kyau, kuma ya dace da abin da aka nuna ɗaya-da-ɗaya. Irin wannan aikin da ake kira ƙidaya. Hanyar da muke sama na kirga abubuwa daya bayan daya ana kiransu kirga daya bayan daya. Idan ana kirgawa gwargwadon kungiyoyi da yawa, ana kiran sa kirgawa.
Yawanci ana amfani da ƙididdigar haɗawa don lissafin adadin kwanakin a cikin kalanda. Galibi, idan ana kirga kwanaki 8 daga Lahadi: Litinin za ta zama “rana ta farko”, Talata za ta zama “rana ta biyu”, kuma Litinin ta gaba za ta zama “rana ta takwas”. Lokacin kirgawa a fakaice, Lahadi (ranar farawa) za ta zama “ranar farko”, sabili da haka Lahadi ta gaba za ta zama “rana ta takwas”. Misali, makonni biyu a cikin Faransanci jours ne (kwanaki 15). Hakanan, a cikin Girkanci (δεκαπενθήμερο) da Spanish (quincena), ana amfani da lambar 15 azaman tushe. Hakanan ana amfani da wannan al'ada ga sauran kalandar: a kalandar Roman, nons (tara) kwana takwas ne kafin ides; a cikin kalandar Miladiyya, Quinquagesima (Lahadi kafin Lent, ma'ana 50) yana Ista ne kwana 49 da suka gabata.
