Numerals in German can be quantitative and ordinal. The former are not inclined, but the latter change as adjectives. But they have something in common - both ordinal and quantitative numerals in a sentence are for the most part a definition. In general, in order to correctly use the numerals, it is enough to remember a few rules.
The rule of composing words to hundreds
So, from 0 to 12 are numerals, which are simple words by the method of education. All of them should not be listed, but as an example: one - eins, two - zwei, three - drei, ten - zehn, etc. These forms are used even when numbering and counting. Suppose, if you want to say: “This is the third lesson”, then it will sound like this: “Das ist Lektion drei”. Those numerals that go from 13 to 19 are complex in their way of education. They are formed by adding to a simple numeral zehn (translation: ten). Everything is actually very easy: 15 - fünfzehn, or 18 - achtzehn. Elementary, you just need to “add” two numbers: 4 + 10 = 14, vier + zehn = vierzehn. In the case of dozens, there is also nothing complicated, such numerals in German are obtained after adding –zig. The suffix in this regard is everything: dreißig - 30, siebzig - 70, neunzig - 90, etc. The same rule of addition applies here, only the notorious suffix is added to the simple numeral: fünf + zig = fünfzig (50). Nothing too complicated. But the numerals in German from 21 to 99 must be read from right to left, not forgetting to separate the two digits with the word-union und (translation: and). Similarly, the rule of addition applies, for example, 33 - drei (3) und (and) dreißig (30) = dreiunddreißig. Or 91 - ein (1) und (1) neunzig (90) = einundneunzig.
The rule of using quantitative numbers
There are many rules that should be followed when using this part of speech. Quantitative numerals in German can be used as you like. Suppose a person asks if his interlocutor has pencils: “Haben Sie Bleistifte?”, And he answers him: “Ja, einen”. From this example it can be seen that the number “one” determined the number of pencils a person has, but without indicating a noun. And there is another example. If the answer was: “Ja, einen schwarze Bleistift und einen blaue Bleistift” - here you can clearly see the noun, even two, because this sentence is translated as “Yes, one black pencil and one blue”.
Numerals in German as Nouns
It could be like that too. If expressed more competently, then numerals can play their role. Suppose die Million, die Milliarde, die Billion, as well as zwei Millionen, neun Milliarden, sechs Billionen. These combinations are commonly used in determining monetary amounts, although they are also used in other contexts. As you can see, these numbers have articles, and they are also written separately with the use of another numeral. This is their difference from the rest of the examples.
Ordinal education
Here, as in the case of the previous group, there are some peculiarities. Ordinary numerals in German are correctly written in numbers and put a dot on the end. From 2 to 19 they are formed with the help of –t, in this way: vierzehnt-, acht-, fünfzehnt- ... and at the end it is obligatory to add an ending - it is used in the same way as for adjectives. For example, vierzehnte Student (fourteenth student). German numerals of this group, starting from 20, are formed using –st, for example: achtundvierzigst-, siebenundneunzigst- ... and endings are added, inclining as in the case of adjectives. It is worth noting that the order begins to be denoted with words such as das erste / die / der, and ends in much the same way, only instead of the first - das letzte. Example: "Das letzte mal trafen wir uns im August" (the last time we met in August) or "Das erste mal habe ich versucht, das Bier in Deutschland" (the first time I tasted beer in Germany). In general, if you understand the use of numerals, then there is nothing complicated in this, the main thing is to be able to correctly apply your knowledge. After all, the main goal in learning German is to master it so that native speakers not only understand what a foreigner is saying, but also confirm that he expresses his thoughts consistently and correctly.