Ngien he yit ke s??-kien tan-vi .

• 365 fe?t-cha 366 ngit = 1 ngien
• 12 ke ngie?t = 1 ngien
• 10 ngien = 1 s??p-ngien
• 100 ngien = 1 s?-ki
• 1000 ngien = 1 chhien-ki