158652

Depending how old he is each year he will need 66 candles altogether but his parent Will need to buy the candles how old he is each year.how we worked it out is 1+2+3=6 4+5+6=15 7+8+9=24 10+11=21 6+15=21 24+21=45 21+45=66.

Challenge2
We will need 33 candles because half of 66 is 33 and how we got 66 is we added 1+2+3+4+5+6+7+8+9+10+11=66 then we halfed it and it equals 33.