Learn Arabic (Modern Standard): شربت أربعة فناجين من القهوة تحت سبع نجوم. - I drank four cups of coffee under seven stars.

In Arabic, numbers 3 to 10 have 'reverse agreement' with the noun they count. To check the gender, we always look at the singular form of the noun. The singular of فناجين (cups) is فنجان, which is masculine. Therefore, the number takes the feminine form أربعة.

Why does 'seven' (سبع) lack the feminine ة ending, even though نجوم (stars) is a non-human plural?

Just like with 'four cups', we look at the singular form of the noun to decide the gender of the number. The singular for 'stars' is نجمة, which is feminine. Because of reverse agreement for numbers 3-10, the feminine noun requires the masculine form of the number, which is سبع (without the ة).

Why are we using the plural words فناجين and نجوم after the numbers here?

For numbers 3 through 10, the counted noun must always be in its plural form. In Arabic grammar, these plural nouns take the genitive case, meaning the number and the noun act together a bit like a possessive phrase (literally 'a four of cups').

How do we know شربت means 'I drank' and not 'she drank' here?

The spoken ending gives it away! 'I drank' is pronounced with a 'tu' sound on the final letter, whereas 'she drank' would end with an 'at' sound. Even without short vowel marks written out, the context of the sentence usually makes it clear who is doing the drinking.