Ivy drinks 2.5 liters of water each day. How many bottles of 2-liter water should Ivy buy for her 4 days consumption?
For 4 days, Ivy consumes 2.5 x 4 = 
<gadget id="calculator">2.5*4</gadget>
<output>10</output>
10 liters of water.
So Ivy should buy 10/2 = 
<gadget id="calculator">10/2</gadget>
<output>5</output>
5 bottles of 2-liter water.

<result>5</result>