Lub teb chaws tus qauv qhia txog 13 Cov qhab nia raug rau cov iav khub rau cov iav. Siv cov lej Arabic 0, 1, 2 Qhov tseeb ntawm txhua qib yog 12, thiab qhov tseeb ntawm qhov seem yog qis tshaj. Qib raug ntawm ob lub zog hauv cov iav khub feem ntau yog tib qib, lossis qib sib txawv tau tso cai. Lub sijhawm no, qib raug ntawm cov iav khub yuav tsum tau txiav txim siab raws li qhov muaj qhov tseeb qis dua.
Ntawm 13 Cov qhab nia raug, cov txheej txheem thev naus laus zis thiab kev ntsuas txhais tau tias qib 0, 1 thiab 2 qhov tseeb tseem nyuaj rau kev nrov thiab yuav tsum tau tsim kho ntxiv. Qib 6 yog theem pib thiab tseem yog qib uas siv ntau hauv kev tsim. Cov kev siv feem ntau siv xws li iav hobbing thiab iav shaping tuaj yeem ua tiav rau lub sijhawm ntev, thiab tuaj yeem ntsuas nrog cov cuab yeej ntsuas dav dav. Peb feem ntau xaiv qib 6-8 hauv cov ntawv thov uas tsis yog qauv.
