The oyster may look like just another slimy sea creature with a shell. But some oysters hold a prize inside: a pearl. Pearls happen when an oyster coats a scratchy grain of sand with smooth stuff called “nacre,” until the layers build up to make a shiny pearl. It can take up to 6 months or even longer.

This bird, called an oystercatcher, probably doesn’t know all that. He just catches oysters and other two-shelled critters to crack them open and eat them. But we people like to eat oysters, so maybe this bird likes pearls? How many oysters does the oystercatcher have to catch to make a necklace for Mom?

*Wee ones:* Who makes a pearl faster, an oyster that takes 4 months or one that takes 7 months?

*Little kids:* If the oystercatcher catches 8 oysters and 3 are holding pearls, how many aren’t? *Bonus:* If the oystercatcher needs 16 pearls in total, at least how many more oysters does he need to find?

*Big kids:* Oystercatchers lay 2-3 eggs in one “clutch” (batch of eggs). If an oystercatcher makes necklaces for all 3 of its kids with 10 pearls on each, how many pearls does it need? *Bonus:* If instead it finds 26 pearls, how many pearls at most can each necklace have if all 3 have to be the same? Will there be any pearls left over?

Answers:

*Wee ones:* The oyster that takes 4 months.

*Little kids:* 5 oysters. *Bonus:* 13 more, since he has only 3 to start.

*Big kids:* 30 pearls. *Bonus:* The necklaces can have 8 pearls apiece at most, since 9 apiece would need 27 pearls in total. There will be 2 unused pearls out of the 26.