Happy Birthday, Anna

It’s my wife’s birthday tomorrow.  I won’t say her age here, but if she lives to 100, how many birthday candles will she have blown out?

It seems two readers have beat me to the punch.  Well played.  They’ve both assumed she has one candle on her first birthday, two on her second, three on her third, etc.  By making two columns of numbers as A has done, you can see that each pair of numbers on a line sums to 101:

1 +100 = 101
2 + 99 = 101
[...]

49 + 52 = 101
50 + 51 = 101

We can then multiply by 50 rows to get the answer,

 50 x 101 = 5,050 candles

Well done, Zachary and A!