Exodus 7:7
Moses was eighty years old and Aaron was eighty-three when they spoke to Pharaoh.

Exodus 7:9
"When Pharaoh tells you, 'Perform a miracle,' you are to say to Aaron, 'Take your staff and throw it down before Pharaoh,' and it will become a serpent."

Deuteronomy 11:3
the signs and works He did in Egypt to Pharaoh king of Egypt and all his land;