som

/ som /

Cases

SingularPluralWhen to use it
nominative som the rouble somla the roubles the plain dictionary form — the doer of the sentence
genitive somnu the rouble's somlanı the roubles' the owner — whose it is
accusative somnu the rouble (as the object) somlanı the roubles (as the object) a specific, known object — whom or what
dative somğa to the rouble somlağa to the roubles direction or recipient — to where, to whom
locative somda at / in the rouble somlada at / in the roubles where it is; also having — mende bar, "I have it"
ablative somdan from the rouble somladan from the roubles 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
my somum my rouble somlarım my roubles
your somuŋ your rouble somlarıŋ your roubles
his / her somu his / her rouble somları his / her roubles
our somubuz our rouble somlarıbız our roubles
you all's somuğuz you all's rouble somlarığız you all's roubles
their somları their rouble somları their roubles

The overlap in the last rows is real, not a mistake: somları can mean "his / her roubles", "their rouble", or "their roubles" — context decides.