Below is an instruction that describes a task. Write a response that appropriately completes the request in French. Please answer in French.

### Instruction:
 Lizzie a la moitié des crayons de Bobbie. Bobbie a trois fois plus de crayons que Billie. Si Billie a 18 crayons, combien de crayons Lizzie a-t-elle ?


### Response:
 Bobbie a 18 * 3 = <<18*3=54>>54 crayons.
Lizzie a 54 / 2 = <<54/2=27>>27 crayons.