The Levite must set aside a tenth of his tithe for the priest

"Moreover, you shall speak to the Levites and say to them, 'When you take from the sons of Israel the tithe which I have given you from them for your inheritance, then you shall present an offering from it to the LORD, a tithe of the tithe.

Hebrew

כו וְאֶל-הַלְוִיִּם תְּדַבֵּר, וְאָמַרְתָּ אֲלֵהֶם, כִּי-תִקְחוּ מֵאֵת בְּנֵי-יִשְׂרָאֵל אֶת-הַמַּעֲשֵׂר אֲשֶׁר נָתַתִּי לָכֶם מֵאִתָּם, בְּנַחֲלַתְכֶם--וַהֲרֵמֹתֶם מִמֶּנּוּ תְּרוּמַת יְהוָה, מַעֲשֵׂר מִן-הַמַּעֲשֵׂר.

Greek

26 Καὶ τοῖς Λευίταις λαλήσεις καὶ ἐρεῖς πρὸς αὐτούς Ἐὰν λάβητε παρὰ τῶν υἱῶν Ισραηλ τὸ ἐπιδέκατον, ὃ δέδωκα ὑμῖν παρ᾿ αὐτῶν ἐν κλήρῳ, καὶ ἀφελεῖτε ὑμεῖς ἀπ᾿ αὐτοῦ ἀφαίρεμα κυρίῳ ἐπιδέκατον ἀπὸ τοῦ ἐπιδεκάτου.

• Parashah: Korach
• Sefer HaChinuch: 396
• Mishneh Torah: Seeds — Heave Offerings

• Numbers 18:26

Enumeration and classification from BibleData. The Greek is the Septuagint reading of the same verse, carried by the source for comparison.