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十年期化成年 = dekad ke tahun 从 dekad 换成年是大单位换小单位，要用乘法：一个 dekad 有十年，所以把 dekad 的数目乘十，再写 tahun。 例子：4 dekad → 4 × 10 = 40 tahun。 注意：乘十只在后面加一个零；加两个零就变成了 abad 的换算。

decades to years = dekad ke tahun Dekad to years goes from a bigger unit to a smaller one, so multiply: one dekad has 10 years, so multiply the number of dekad by 10 and write tahun. Example: 4 dekad → 4 × 10 = 40 tahun. Watch out: multiplying by 10 adds one zero; adding two zeros is the rule for abad.

千年与世纪 = alaf dan abad 两个单位都先换成年：一个 alaf 是一千年，一个 abad 是一百年。再问：一千年里有几个一百年？用除法就能求出。 例子：3 alaf = 3 000 tahun，3 000 ÷ 100 = 30 abad。 注意：相邻的两个单位之间是十倍的关系，不是一百倍或一千倍。

millennium and centuries = alaf dan abad Change both units into years: one alaf is 1 000 years and one abad is 100 years. Then ask how many hundreds are in a thousand; division gives the answer. Example: 3 alaf = 3 000 tahun, and 3 000 ÷ 100 = 30 abad. Watch out: neighbouring units differ by ten times, not by a hundred or a thousand times.

年化成十年期 = tahun ke dekad 从年换成 dekad 是小单位换大单位，要用除法：看年数里有几个十年，就是几个 dekad。 例子：50 tahun → 50 ÷ 10 = 5 dekad。 注意：换成大单位时数字会变小；如果数字变大，就是乘错了。

years to decades = tahun ke dekad Years to dekad goes from a smaller unit to a bigger one, so divide: the number of tens in the years is the number of dekad. Example: 50 tahun → 50 ÷ 10 = 5 dekad. Watch out: changing to a bigger unit makes the number smaller; if it gets bigger, you multiplied by mistake.