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

### Instruction:
 詹姆斯有18块巧克力棒要卖给游泳队。他上周卖了5块，这周卖了7块。他还需要卖多少块巧克力棒？


### Response:
 到目前为止，他已经卖了5 + 7 = <<5+7=12>>12块巧克力棒。
詹姆斯还需要卖18 - 12 = <<18-12=6>>6块巧克力棒。