To solve the problem, we need to determine how many stickers Reann started with based on the information provided. Let's break down the operations:
- Reann gives half of her stickers away.
- After giving away half, her brother gives her 8 stickers.
- Reann ends up with 12 stickers.
Let \( x \) be the number of stickers Reann started with.
After giving away half, she has \( \frac{x}{2} \) stickers left. Then, after receiving 8 stickers from her brother, her total is:
\[ \frac{x}{2} + 8 = 12 \]
To solve for \( x \), we first subtract 8 from both sides:
\[ \frac{x}{2} = 12 - 8 \]
\[ \frac{x}{2} = 4 \]
Next, we multiply both sides by 2 to find \( x \):
\[ x = 4 \times 2 \]
\[ x = 8 \]
Reann started with 8 stickers.
The operations used in this problem are subtraction and multiplication.
So, the correct response is:
- subtraction and multiplication.