When should I use 兆 instead of 万亿?

Question

In the following sentence:

据悉，日本政府此次提出了在东京奥运会召开的2020年，使访日游客增至4000万人次，消费额达到8万亿日元的目标。

In this sentence, 万亿 is used instead of 兆, to express 10^12 digit.

In Chinese, now 兆(zhào) might be rarely used to express "trillion" and instead 万亿 is used.

So when should I use 万亿 and when 兆 to express such a large number?

And also what about the case to express more than 万亿, such as 10^16?

Japanese use 万, 亿, 兆, 京... but how about Chinese? Should I write it as 91万万亿2513万亿522亿6915万159 to express 912513052269150159? or 91京2513兆522亿6915万159?

Answer 1

兆 was used in ancient China to represent trillion, it is no longer used in mainland China, but still used in Taiwan, it uniquely represents the mega prefix in the International System of Units currently. But in Taiwan, 一兆 means one trillion, while 兆赫兹 means MHz (megahertz). The largest number that can be expressed in a single Chinese character is 亿 in mainland China, to express larger numbers, use the phrases like 万亿 or 亿亿. Of course, there are also Chinese characters that represent numbers larger than 亿 (100 million), but such a large number is not used generally, and nobody use them, except the ancient literature. You may learn them here.

Answer 2

I am a Chinese PhD student studying computer science and communication engineering in London. I guess I might be the right person to give you the answer.
兆 is usually used in IT context. If you use 万亿 in the context of IT, that would be weird. Except this, you can use 万亿 all the time.

Answer 3

There are several historical counting systems in Chinese, many of those use the same character to represent different values. Although there is a standard counting system today, the remnant 兆 causes confusion.

The character 兆 in mainland China refers to a million. However, 兆 in Taiwan refers to this number 1,000,000,000,000.

The reason I wrote out 1,000,000,000,000 is that interestingly, English has the same confusion, since there exist not only one counting system in English, namely "the long system" and "the short system". In "the long system", 1,000,000,000,000 is referred to as a "billion"; in "the short system", 1,000,000,000,000 is referred to as a "milliard". This discrepancy cause lots of transatlantic confusions.

In Chinese, , this confusion is easily avoidable. Since 万 means 10,000 and 亿 means 100,000,000 across all systems, 万亿 is no doubt 1,000,000,000,000.

Answer 4

According to Chinese (mainland) national standard, only the metric prefix "mega-" (for 10⁶) is 兆, while a trillion (10¹²) should always be 万亿, never 兆.

e.g. 一兆字节 (or 一兆 for short) means one megabyte (1 MB), and 一兆赫 means one megahertz (1 MHz).

http://zjj.beijing.gov.cn/wsbs/infoview.asp?ViewID=50494

10的6次方 兆 M

10的4次方称为万，10的8次方称为亿，10的12次方称为万亿

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In Taiwan, most people use 兆 for 10¹².

Answer 5

我想你大概不小心把“兆开”写错了，你应该是想写‘召开’。

如今很少有人用兆来表示百万，我们更习惯直接说百万。兆现在是网络流量或电量的单位。

zdic.net 　3. 数名，等于百万（古代指万亿）：兆周（电磁波频率单位，每秒一百万周的频率为一兆周）。

Nowadays, I hear not, many people write 兆, except when you want to express an extremely large amount.

Answer 6

Number over five digitals, namely beyond 萬, there are several ways of counting. 億兆京 has several interpretations. This causes discrepancy in meaning. In tradition, to avoid ambiguity, 萬萬, 十萬萬, 百萬萬, 千萬萬, 萬萬萬, 十萬萬萬... is used instead.

There are three interpretation of 一兆.

1. 一百萬 = 10⁶. Current it is found in some Chinese prefix of SI Units. 1 MHz = 一兆赫.
2. 一萬萬萬 = 10¹². Big numbers count in Hong Kong, Japan, South Korea and Taiwan.
3. 一萬萬萬萬 = 10¹⁶.

Answer 7

Mainland China:

91 2513 0522 6915 0159 = 91亿2513万522亿6915万159 (91亿亿)

1 MB = 1兆字节

Taiwan:

91 2513 0522 6915 0159 = 91京2513兆522亿6915万159

1 MB = 1百万字节