וְלָקַחְתָּ֗ חֲמֵ֧שֶׁת חֲמֵ֛שֶׁת שְׁקָלִ֖ים לַגֻּלְגֹּ֑לֶת בְּשֶׁ֤קֶל הַקֹּ֙דֶשׁ֙ תִּקָּ֔ח עֶשְׂרִ֥ים גֵּרָ֖ה הַשָּֽׁקֶל׃
tu prendras cinq sicles par chaque tête; tu les prendras selon le poids du sanctuaire, à vingt ghéra le sicle,
Rashbam
תפדה, after the Levites had been sanctified to take the place of the firstborn who had participated in the sin of the golden calf, in the second year after the Tabernacle had been erected and inaugurated. At that time you will take 5 shekalim per head (Numbers 3,47) to effect this exchange. It included Levites of one month and up (males) Numbers 18,16)