How many presents on the 12th day of Christmas?

23 December 2019

Interview with 

Amalia Thomas, University of Cambridge

CHRISTMAS SACK OF PRESENTS

Santa's sack

Share

Right, time to find out how many presents Amalia Thomas is expecting come the 12th day of Christmas, given that, each day, she gets a new present, plus all the presents she got on each of the preceding days again. It's laborious to calculate if you add it up the old-fashioned way. Luckily, maths can come to the rescue with a clever trick to make the calculation easier...

Comments

Hi, during the podcast you mentioned that the total number of presents were 288.
Shouldn’t it be 364 instead? Here is the math for that:
https://www.mathscareers.org.uk/article/the-maths-inside-the-twelve-days...
Also, 364 can be seen as one gift for each day of the year apart from Christmas Day :)

Father Christmas isn't the only red-faced one this year! Amalia admits that she made a mistake and got the answer wrong!

Add a comment