<human>:  Caleb is baking a birthday cake for his grandfather. His grandfather is turning 79 years old. Caleb puts three colors of candles on the cake. He puts one candle for each year for his grandfather. He puts 27 yellow candles, 14 red candles and the rest are blue candles. How many blue candles did he use?
<bot>: How many yellow and red candles did Caleb put on the cake? ** Caleb has put 27 + 14 = <<27+14=41>>41 yellow and red candles.
How many blue candles did Caleb use? ** So, he used 79 - 41 = <<79-41=38>>38 blue candles.
#### 38