What does the X in ID number 18 mean?

The x at 18 on the ID card should be read as shí.

Before Arabic numerals were introduced into Europe, Europeans always counted with Roman numerals. The rules are as follows:

I = 1； x = 10； c = 100； M= 1000

v = 5； L = 50D=500？

The smaller number is on the right, let them add up, for example, ⅷ = 8, =12; If the smaller number is on the left, let them be subtracted, such as Ⅳ = 4 and Ⅶ = 9. ?

Roman numerals not only appear on clocks and watches, but also indicate the year when TV programs were produced, such as? MMXXI 、? MMXX 、? MMXIX 、? MMXVIII、MMXVII 、? MMXVI, corresponding to 202 1, 2020, 20 19, 20 18, 20 17, 20 16 respectively.

Mysterious x

In the field of science and technology, X symbolizes "experiment", "exploration" and "innovation" and becomes the abbreviation of experimental. For example, Space X, which carries Musk's dream of emigrating to Mars, is called Space Exploration Technologies, and X stands for exploration.

Google's department specializing in scientific research and development is called Google X, and X stands for its innovative spirit. But the X in Apple's iPhone X is to commemorate the 10th anniversary of the release of Apple's mobile phone, and X is Roman numeral 10.

Please refer to the paper -X with ID number 18 for the above contents. Read what?