They came in educational kits usually to teach small children how to count money and make change ( subtract). Today, many 99Cent stores have small pkg of them.
I cannot open/see your pictures, but plastic coins in all denominations are used in early childhood education to introduce children to counting money. My mother teaches and has them in her classroom. Interestingly enough, the dates always seem to be 1983. I know this because I always ask why they don't use more recent dates. My guess is it's the birth year of a worker or something of the sort at the factory.
if you would like to see plenty of them, visit www.plastic-play-money.org which is my on-line collection catalogue.
