What does MILU stand for? 

Milü

The name Milü, also known as Zulü, is given to an approximation to π found by Chinese mathematician and astronomer Zǔ Chōngzhī. He computed π to be between 3.1415926 and 3.1415927 and gave two rational approximations of π, 227 and 355113, naming them respectively Yuelü 约率 and Milü. 355113 is the best rational approximation of π with a denominator of four digits or fewer, being accurate to 6 decimal places. It is within 0.000009% of the value of π, or in terms of common fractions overestimates π by less than 13 748 629. The next rational number that is a better rational approximation of π is 52 16316 604, still only correct to 6 decimal places. To be accurate to 7 decimal places, one needs to go as far as 86 95327 678. An easy mnemonic helps memorize this useful fraction by writing down each of the first three odd numbers twice: 1 1 3 3 5 5, then dividing the decimal number represented by the last 3 digits by the decimal number given by the first three digits. Zu's contemporary calendarist and mathematician He Chengtian invented a fraction interpolation method called "harmonization of the divisor of the day" to obtain a closer approximation by iteratively adding the numerators and denominators of a "weak" fraction and a "strong" fraction. Zu Chongzhi's approximation π ≈ 355113 can be obtained with He's method

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