Natalie's sister had 8 small diaries in her locker. Last summer she bought double the number of diaries she had and then lost 1/4 of what she had. How many diaries does Natalie's sister have now?
Natalie's sister bought 2 * 8 = 
<gadget id="calculator">2*8</gadget>
<output>16</output>
16 diaries.
So she then had 16 + 8 = 
<gadget id="calculator">16+8</gadget>
<output>24</output>
24 diaries.
Afterwards, she loses 1/4 * 24 = 
<gadget id="calculator">24*1/4</gadget>
<output>6</output>
6 diaries.
So, Natalie's sister now has 24 - 6 = 
<gadget id="calculator">24-6</gadget>
<output>18</output>
18 diaries.

<result>18</result>