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?
Let’s work this out in a step by step way to be sure we have the right answer.
18
Natalie's sister bought 2 * 8 = 16 diaries.

So she then had 16 + 8 = 24 diaries.

Afterwards, she loses 1 / 4 * 24 = 6 diaries.

So, Natalie's sister now has 24 - 6 = 18 diaries.

.

Thus, the answer is 18