Birthday Cake Candles

 

 
 

Baby Ben is turning one.  His parents are planning to celebrate his first birthday with a special cake which will have one candle on it.
They think about future birthdays too, when they will need more and more candles.
They are curious to know how many candles they will need to buy for his birthday cakes, up to and including his eleventh birthday...
 

If candles last less than a year, how many candles will they need for Ben's cakes, up to and including his eleventh birthday?
How do you know?

What if the candles are able to last for longer than one year?
How many candles will they need for his cakes, up to and including his eleventh birthday now? 
How did you work this out?