1. To find the missing top number in a subtraction problem, you can add the other two numbers. What is the value of $k$ in the equation $k - 7 = 11$?
2. A baker made 30 cupcakes. She sold some, and now she has 18 left. Which equation finds the number of cupcakes, $c$, that she sold?
3. Use the 'subtract down' method to find the missing number. If $28 - p = 15$, what is the value of $p$? The answer is ___.
4. After giving 9 stickers to a friend, Leo had 14 stickers left. What was the total number of stickers, $s$, that Leo had at the start?
5. Solve for the variable $m$ in the following equation: $m - 12 = 12$. The value of $m$ is ___.
6. Solve for the missing number in the equation: $\_\_\_ - 15 = 42$.
7. To solve the problem $? - 31 = 55$, which operation should you use to find the missing number?
8. A bakery had some cookies. After selling 28 cookies, there were 45 cookies left. How many cookies did the bakery have to start with? The answer is ___.
9. Find the missing number that makes this sentence true: $78 - \_\_\_ = 25$.
10. Leo had 62 dollars. He spent some money on a toy and had 34 dollars left. How much did the toy cost?