plüs

/plys/

Cases

SingularPluralWhen to use it
nominativeplüsthe plus signplüslethe plus signsthe plain dictionary form — the doer of the sentence
genitiveplüsnüthe plus sign'splüslenithe plus signs'the owner — whose it is
accusativeplüsnüthe plus sign (as the object)plüslenithe plus signs (as the object)a specific, known object — whom or what
dativeplüsgeto the plus signplüslegeto the plus signsdirection or recipient — to where, to whom
locativeplüsdeat / in the plus signplüsledeat / in the plus signswhere it is; also having — mende bar, "I have it"
ablativeplüsdenfrom the plus signplüsledenfrom the plus signswhere it comes from; also "than" when comparing
When to use each case
nominative
the plain dictionary form — the doer of the sentence
genitive
the owner — whose it is
accusative
a specific, known object — whom or what
dative
direction or recipient — to where, to whom
locative
where it is; also having — mende bar, "I have it"
ablative
where it comes from; also "than" when comparing

The endings are the same ones the pronouns wear — that page explains when each case is used.

With an owner

One ownedSeveral owned
myplüsümmy plus signplüslerimmy plus signs
yourplüsüngyour plus signplüsleringyour plus signs
his / herplüsühis / her plus signplüslerihis / her plus signs
ourplüsübüzour plus signplüsleribizour plus signs
you all'splüsügüzyou all's plus signplüslerigizyou all's plus signs
theirplüsleritheir plus signplüsleritheir plus signs

The overlap in the last rows is real, not a mistake: plüsleri can mean "his / her plus signs", "their plus sign", or "their plus signs" — context decides.