"He is sixty."
Translation:Él tiene sesenta años.
I put tiene sesenta anos and it marked it wrong, do you need the El with age?
Think DL wanted you to add the subject pronoun, el. Needed with ages? Not necessarily. The take-away here is that the verb tenir is used with ages in Spanish which is different from English.
He is sixty - means - El tiene sesenta. you do not have to put the age afterwards in English. You would just say - He is sixty. - You do not have to put - years old afterwards. My keyboard does not have a accent sign to put on the (El) sorry English keyboard.
You can use alt-codes to enter accented characters. I use these in the comments sections. To use them, hold down your Alt key and press the numbers in order on the num-pad, then let go of Alt. Some useful ones: Alt+133 = à Alt+130 = é Alt+141 = ì Alt+149 = ò Alt+151 = ù Alt+144 = É Alt+164 = ñ