They showed his signs among them; literally, the matters of his signs; i.e. his long series of signs. Aaron showed the earlier signs generally (Exodus 7:10, Exodus 7:19, Exodus 7:20; Exodus 8:6, Exodus 8:17), Moses the later ones (Exodus 9:10, Exodus 9:23; Exodus 10:13, Exodus 10:22).
And wonders in the land of Ham (comp. Psalms 105:23 and Psalms 106:22).