# "The sum of three and five is eight."

February 9, 2016

## 19 CommentsThis discussion is locked.

Whats going on here?

Three different number forms are being used in the same sentence, and to me it appears as if they are all being used in the same way??

Is the point of this one to show that all three forms are valid when you are doing maths like this and not referring to nouns?

"Trzy" and "pięć" are used in Genitive. You can just say: "Trzy plus pięć to/równa się osiem".

Ah, I see... it's because "suma" takes the genitive....

When I write it like this in English it makes sense:

"the sum of three (gen.) and of five (gen.) =(/"to") eight (nom.)"

..and they used the masc. gen. of trzy = "trzech", instead of the other gen. of trzy = "trzej"

Dzięki za odpowiedż!

trzej is nominative. only other genitives of three are trojga (from troje), and trójki (from trójka) We usually use masculine numerals in maths.

Dzięki za pomoc!

You can also translate it to "Sumą trzech i pięciu jest osiem".

Więc: suma i sumą są dobrze - ale dlaczego??

"Suma trzech i pięciu to osiem" vs "Sumą trzech i pięciu jest osiem".

It's our usual "X is Y" sentence, but turned around, to "Y is X" because it seems pretty probable here - in fact, it makes more sense to put "osiem" in the end as this is like a maths equation and therefore "eight" is the 'new information'.

Also: Eight is 'a sum', but it's hard to say that 'the sum' is 'an eight', so you wouldn't put eight in Instrumental.

Why not "Suma z trzech i pięciu to osiem"?

The sum of three and five is eight - Suma trzech i pięciu wynosi osiem

Ok, added as an alternative translation.

why not 'suma trzech i pięciu jest osmioma'?

In a sentence like:

[noun in nominative] jest/są [noun in instrumental]

you need to make sure that the nominative noun is a subset of the instrumental noun.

8 is a possible sum. If you add different numbers together, you'll potentially get a different sum. But those will all be sums, hence the number 8 is one possible subset of the term 'sum'. Therefore the noun 'sum' must take the instrumental case, whereas '8' stays in nominative.

I answered Suma trzech i pięciu jest osiem.

I got a hint that I should have have used sumą. Is it instrumental because somehow Osiem jest sumą trzech i pięciu?

Exactly! Forgetting 3 and 5 for a moment, we could say that "Eight is a sum". So "suma" takes Instrumental.

Trochę to dziwne , napisałem,,suma trzy i pięć to osiem,, i nie uznało. A co jest nie tak z taką formą?

No, jakby to delikatnie ująć... gramatyka. "suma czego i czego", potrzebny jest dopełniacz.