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Are There More Twins or Triplets Out There?

by Derek Stump

Do you know any twins? Twins are siblings born on the same day! Sometimes twins are “identical”, which means they look exactly alike. About 3 in 100 kids are twins, and 1 in 100 are identical twins. But even more rare are triplets, when three kids share the same parents and birthday. Triplets are 1 in 1,000! And then there are quadruplets – 1 in 8,000 – and quintuplets – 1 in 20,000 kids. The real math question is, when do we need to get a second cake?    


Wee ones: Which are there more of: days that are your birthday, or days that aren’t your birthday? 
Little kids: If your neighborhood celebrates a pair of twins’ birthdays on Tuesday, a set of triplets’ birthdays on Wednesday, and your own birthday on Thursday, how many kids celebrate birthdays that week? Bonus: If a group of quintuplets – 5 siblings – is running around and all but 1 of them are wearing sneakers, how many sneakers is the group wearing? 
Big kids: Which party has more kids: 5 pairs of twins, or 4 sets of triplets? Bonus: How many pairs of twins would it take to equal 30 sets of triplets?  

Answers:

Wee ones: Days that aren’t your birthday – that’s why it’s special! 
Little kids: 6 birthdays: 2 + 3 + 1. Bonus: 8 sneakers: 4 kids with 2 sneakers each. 
Big kids: The triplets: 12 kids compared to 10. Bonus: 45 pairs of twins.

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