You’ve spent the last year building your home. Now it’s time to add an important part to your project. When you go to the hardware store to get what you need, the items are priced as follows:

1. One will cost $5.
2. Two will cost $5.
3. Twelve will cost $10.
4. A hundred forty-four will cost $15.

 What are these items?

 solutioin:

https://bit.ly/2lRyTMk