Construction Paper Scissors Marker/Pen Googly Eyes Tray Bowl
Once you have all 10 heads, draw simple mouths (and noses, if you wish) and label each of them with a number from 1-10.
Set all 10 heads on a small tray along with a bowl of googly eyes. Make sure the eye match the exact number you need.
Set your child up at a table or on a mat (we use cloth place mats for work like this) and let him give all of the aliens eyes!