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

### Instruction:
 Tommy anataka kupata pesa za kununua vitabu vipya 8. Kila kitabu kina gharama ya $5. Ikiwa Tommy tayari ana $13, anahitaji kuokoa kiasi gani?


### Response:
 Vitabu vitagharimu $40 kwa sababu 8 x 5 = <<8*5=40>>40
Anahitaji kuokoa $27 kwa sababu 40 - 13 = <<27=27>>27