Tehillim: The different Numbering Systems of the Psalms

The Book of Psalms (Hebrew: תְּהִלִּים, Tehillim, “praises”), is the first book of the Ketuvim (“Writings”), the third section of the Hebrew Bible, and thus a book of the Christian Old Testament. The title is derived from the Greek translation, ψαλμοί, psalmoi, meaning “instrumental music” and, by extension, “the words accompanying the music”. The book is an anthology of individual psalms, with 150 in the Jewish and Western Christian tradition and more in the Eastern Christian churches. Many are linked to the name of David, but his authorship is not accepted by modern scholars.

In different lists of Bible‘s translations some Psalms have a different number in brackets (or in the margin). Some Bibles have a V in the margin and a different number beside it. This other number is the number of the Psalm in the Latin Vulgate translation. Thus V in the margin = Vulgate. This was a translation of the original Greek (the Septuagint, LXX). In the USA ,the Psalm numbering follows the number in the Hebrew, however in Catholic Missals and Mass leaflets in some other countries the numbering follows the Vulgate/Septuagint, even though a translation of the Hebrew text: Example Psalm 139(138). This cause a great confusion among the believers.
The following table gives you the conversion of the different numbering systems:

(MT stands for Masoretic Text. Since the 6th century AD Jewish rabbis called Masoretes copied the Hebrew text, hence Masoretic Text).