John Gill Commentary Numbers 7:15

"one young bullock, one ram, one he-lamb a year old, for a burnt-offering;" — Numbers 7:15 (ASV)

One young bullock
Of three years old, as the Targums of Jonathan and Jerusalem:

one ram ;
of two years old, as the same Targums:

one lamb of the first year, for a burnt offering ;
of which see (Leviticus 1:3Leviticus 1:10) .