Numbers 23:2-3

23:2 So Balak did just as Balaam had said. Balak and Balaam then offered on each altar a bull and a ram. 23:3 Balaam said to Balak, “Station yourself by your burnt offering, and I will go off; perhaps the Lord will come to meet me, and whatever he reveals to me I will tell you.” Then he went to a deserted height.

Numbers 23:29-30

23:29 Then Balaam said to Balak, “Build seven altars here for me, and prepare seven bulls and seven rams.” 23:30 So Balak did as Balaam had said, and offered a bull and a ram on each altar.