In Chinese, there are only TEN characters you need to learn before you can express basically every number including the extremely huge ones. These ten characters are:
零(líng) ----- zero ----- 0
一(yī) ----- one ----- 1
二(èr) ----- two ----- 2
三(sān) ----- three ----- 3
四(sì) ----- four ----- 4
五(wǔ) ----- five -----5
六(liù) ----- six ----- 6
七(qī) ----- seven ----- 7
八(bā) ----- eight ----- 8
九(jiǔ) ----- nine ----- 9
十(shí) ----- ten ----- 10
百(bǎi) ----- hundred ----- 100
千(qiān) ----- thousand ----- 1000
万(wàn) ----- ten thousand ----- 10000
亿(yì) ----- hundred million ----- 100000000
So you might be wondering: how do we Chinese express numbers between 10 and 100, 100 and 1000 and so on since the words don't conjugate? The answer is simple: by arithmetic rules, we just tie two characters together to form a compound word for those numbers. Number words in Chinese functions similarly as Roman numerals: given two consecutively placed characters for numbers, when a smaller number is tied after a bigger one, we add them together; when a smaller number is put before a bigger one, we multiply them together. By this rule, we can express any numbers using only nine characters through calculations!
Let's look at some examples:
-十七: literally translated as "ten seven", you could see the smaller number "seven" is placed after the bigger one "ten", so we add seven to ten and get — you're right, seventeen!
-三十: now this one is "three ten", or "three tens" in a sense. Three, the smaller one, is before the bigger one, ten, so we take three times ten and this word means thirty!
-六十一: this starts to be a little bit more complex. We firstly notice "six" is before "ten", so we multiply them to get a sixty. Then there's another "one" after it, so we add one to sixty. Thus this word represents sixty-one.
(Tip: you may have already noticed by now that the order of operations to get a compound Chinese number word is exactly the same as the four arithmetic rule: multiply first before addition.)
-二百五十三: this is getting even more complex. Adhering to the rule mentioned in the last example, we firstly multiply a hundred by two and ten by five, then add everything together. In short, this word can be figured out by 2×100+5×10+3=253, two hundred and fifty-three.
-十二万六千: here may cause you some confusion as you'll find that with the rule above, you're gonna get 10+2×10000+6×1000=26010 which is incorrect. Now, in Chinese, 万 is like "thousand" in English, before which you can put a number more than nine. (What I mean by this is that it makes sense to say "eleven thousand" while not if you say "eleven hundred".) Therefore, any number before 万 that is within the range 1 to 9999 is considered as a entirety. So you need to multiply 万 with the whole number before it. In this case, it's 12×10000+6×1000=126000. The same rule goes for 亿.
Notice: another difference in Chinese number words is we divide big numbers in 4-digit groups. This is why Chinese has a character for ten thousand (万) and a hundred million (亿). In contrary, we use compound words instead to express "million" "billion" etc.. (million is 百万, billion is 十亿)
Now let's move to a slightly more advanced level.
The use of "0" in Chinese
Zero is an extremely important number, especially in Chinese, because there would be so many ambiguities in modern Chinese expressions of numbers if zero was not introduced. For instance, let's look at these three numbers:
-一百五(yī bǎi wǔ)
-一百五十(yī bǎi wǔ shí)
-一百零五(yī bǎi líng wǔ)
Applying the rules you've just learned in the previous session, you may get confused and wonder: aren't the first and last numbers the same? You take 100+5=105 and 100+0+5=105 but only find out later that in fact the first and second numbers are the same. Then you get even more confused because 100+5 obviously can't be equal to 100+5×10!
However, here is the thing: when 十, 百, 千 are not included in the first 4-digit group in a number and the digits after them are only occupied by zero, we often omit them in spoken language. So numbers like 130, 1300, 13000 are also spoken as 一百三（十）, 一千三（百） and 一万三（千）. Hence in this example, 一百五 actually means 150!
By this, we clearly see the fact that how huge a confusion will occur if zero is not used in modern Chinese. A zero helps indicate the "empty" digits in a number to avoid ambiguity. Here are rules of the use of zero:
1. if after a digit of a number, all the rest of the digits are zero, those zeros are not spoken.
2. if there's a zero in between two digits when the number is written in Arabic Numerals, the zero is spoken to indicate the "empty" digit. The pronunciation is "líng"(零).
3. Only one zero is pronounced no matter how many are there as long as they are in consecutive digits.
Here are some examples:
-10000: although there are 4 zeros in the number, since they are all at the end of the number, they're not pronounced. So this is 一万 instead of 一万零, just like in English we say "ten thousand" instead of "ten thousand zero" or that sort of weird things.
-101: in this 3-digit number, the 1st and 3rd digits are occupied by 1 and a zero is in between. Since after zero there's still an occupied digit, it should be pronounced. So this is 一百零一.
-10001: so here is what I mean by "zeros in consecutive digits". Firstly we can tell that zero should be pronounced as a 1 is after all the zeros. But despite there're three zeros next to each other, we don't say it thrice. Instead, we only pronounce one zero. So this is 一万零一.
-10050: now try to combine those rules together. The two zeros between 1 and 5 are consecutive, so only one zero is pronounced. And the zero at the end is not pronounced as there's no more digit. In conclusion, this is supposed to be 一万零五十.
-1010: the reason why I show a seemingly identical example as the last one is that there is a small little detail that needs to be noticed. Though we know that 10 is pronounced as 十, we don't say 一千十 here as it sounds rather awkward. To obtain a smoother flow and rhythm of the voice, this is pronounced as 一千零一十.
Decimals in Chinese (decimals ----- 小数(xiǎo shù) ----- "tiny numbers")
In English, there're several ways to pronounce a decimal. For example, for 3.15 we can say "three point one five" or "three fifteen"; for 0.08 we can say "zero point zero eight" or less formally "zero point O eight". However, in Chinese there is only one way to say a decimal. The decimal point is read as 点(diǎn) (but its name itself is 小数点 xiǎo shù diǎn). And everything after the decimal point you just read them one by one. As simple as that, right? Let's look at some examples:
-1.15: 一点一五(yī diǎn yī wǔ). So although after the decimal point the thing seems to be fifteen you pronounce them individually. This is the same as the ordinary way to do it in English.
-1.10030: 一点一零零三零(yī diǎn yī líng líng sān líng). One thing you should have noticed here is that the rules of zero's not applicable for decimal places. After the decimal point, no matter where the zero is and how many zeros there are, every individual numeral is required to be read out.
Fractions in Chinese (fractions ----- 分数 ----- "divided numbers")
Fractions might not be heard as frequently as decimals but are still quite commonly used. Same as decimals, whilst you may have two ways to say the fraction 2/3 in English as "two thirds" and "two over three", generally there's only one way to say it in Chinese for daily conversations.(if you want to discuss about mathematics we do have other ways but who will be so mathematical in casual conversations?) In Chinese, the numerator and the denominator are pronounced as integers as usual, the fraction line is read as 分之(fēn zhī) (again its name itself is 分数线 fēn shù xiàn). So, take 2/3 as an example. In Chinese you say it as 三分之二, which is a more logical way to express it as it literally means "take two in three parts". One difference between Chinese and English here is that in English you say the numerator first while in Chinese it's denominator first. The rationale behind is you must decide the total portions into which you divide something before you can ascertain how many portions you've taken.
-5/8: 八分之五(bā fēn zhī wǔ)
-1111/3333: 三千三百三十三分之一千一百一十一(no Pinyin for this one because it's gonna be crazily long). This example is to highlight that there's only one way to say a fraction even though it's such a long one.
-8/5: 五分之八(wǔ fēn zhī bā). Even improper fractions also follow the same rule strictly.
Percentages in Chinese (percentages ----- 百分数 ----- "numbers divided by 100")
Percentage has the same difference in ways to pronounce between English and Chinese as fractions. In English we read a percentage by normal reading order, while in Chinese we read the percentage sign first followed by the figure. The percentage sign is read as 百分之(bǎi fēn zhī) (the name of the sign itself is called a 百分号 bǎi fēn hào). So following the rule mentioned, 10% is read as 百分之十(bǎi fēn zhī shí). Make sure you read the sign before the figure.
-0.050%: 百分之零点零五零(bǎi fēn zhī líng diǎn líng wǔ líng). Those rules for decimals are applicable in percentages.
-100%: 百分之一百(bǎi fēn zhī yī bǎi). This is something worth taking down a note. Actually in real life people rarely say 百分之一百. In fact, "一" is often omitted and sometimes even "之" as well. So you would frequently hear 百分之百 or 百分百.
Notice: usually in a news report when percentage is used in a trend to express a rate of increase or decrease, despite saying "上升（下降）百分之三", a more formal and professional way is to say "上升（下降）三个百分点". If you ever watch Chinese news please don't get confused.
This is one of the simplest characters you can find in Chinese so there seems to be no reason to not remember it if you want to study Chinese... Now going back to the main topic, 几 basically means "several" or "a few". It's used to replace any integer between 1 and 10. When it comes to speaking, just add this character in at the digit that needs to be approximated. You can also use 几 alone (with a measure word if required) to express a single-digit number. Let's use some examples to make it clearer.
-十几(shí jǐ): literally means "ten and a few". By saying so, you assume the number is an integer between 10 and 20.
-几十(jǐ shí): when you swap the two characters in the last example, you amazingly get "several tens", which implies the number might be 10, 20, 30, 40, etc. till 90. The same usage is applicable before 百, 千, 万, 亿.
-零点几(líng diǎn jǐ): when used for decimals, since everything after the decimal point is read as single-digit numbers individually, you can use 几 repeatedly to express "zero point something". An approximate number with two decimal places would be, for instance, 零点几几, and with three decimal places, 零点几几几 and so on. See the pattern?
-有几个(yǒu jǐ gè): this literally means "have how many" and you can use it to construct a question to ask for quantities of something which are between 1 and 10.
After learning 几, you may have a question: now I know how to say an approximate figure between 1 and 10, but how about things like "dozens"? No worries, compared to 几, there's another word which can more generally replace any numbers. And that word is 多, which means "many". It functions like the English word "some", by which you'll never know what exactly is the number being referred to. The way to use it is to place it after a confirmed digit. And unlike 几, it cannot be used alone to represent a single-digit number, neither can it go in front the confirmed part of the number. It is used in decimals but much less commonly. Here're some examples:
-一百多(yī bǎi duō): "a hundred and many". By this phrase you're referring to an uncertain quantity within the range 100-200. One thing to take note is that we never say 一百几 in this case, neither do we say 一万几, 一千几 in normal conversations.
-二十多(èr shí duō): it is the same as saying 二十几. The only difference is the latter could be used for a question to ask for further confirmation of the number.
-十多(shí duō): please take note that usually nobody will use this to represent a number itself alone. For a number from 10 to 20 itself, 十几 is the correct way to say it. But when combined with a measure word, such as 个(gè), both 十多个 and 十几个 are correct, only witn the former more frequently seen in formal and literary writing.
-多少(duō shǎo): when you tie the antonym of 多, 少, with it, they form a pronoun used in a question to ask for any quantities. For instance, 多少人(duō shǎo rén) means "how many people" and 多少钱(duō shǎo qián) means "how much (is it)".
If there's a top 100 words list in Chinese, this will probably be included. 左 is left and 右 is right. So this word is literally telling you " left or right", which equals to "around/about" in English. Thus "around 500" in English would appear as "500左右" in Chinese. It's used to say a guessed number with slight difference expected from the actual one. To insert it in your sentence is easy: simply guess a random number, and add 左右 after it!