A notebook costs three times as much as a pen. If a pen costs $1.50, how much will Lyle pay for 4 notebooks?
A notebook costs $1.50 x 3 = $
<gadget id="calculator">1.5*3</gadget>
<output>4.5</output>
4.50.
So Lyle will pay $4.50 x 4 = $
<gadget id="calculator">4*4.5</gadget>
<output>18</output>
18 for the 4 notebooks.

<result>18</result>