This is a subtraction problem because people did not show up for practice, so there will be less people at practice than if everyone had shown up. 

We can start at \(\displaystyle 18\) and count back \(\displaystyle 5\).

\(\displaystyle 18,17,16,15,14,13\)

\(\displaystyle \frac{\begin{array}[b]{r}18\\ -\ 5\end{array}}{ \ \ \space 13}\)

This is a subtraction problem because Tiffany lost balloons so she will have less than what she started with. 

We can start at \(\displaystyle 11\) and count back \(\displaystyle 4\).

\(\displaystyle 11,10,9,8,7\)

\(\displaystyle \frac{\begin{array}[b]{r}11\\ -\ 4\end{array}}{ \ \ \ \space 7}\)

This is a subtraction problem because we want to know how many of the total treats Spot has eaten. We take the total number of treats and then subtract the number of treats that are left in the box. \(\displaystyle 100-52=48\).

This is a subtraction problem because we want to know how many balls are left over after each boy takes one. We start with the number of balls and then subtract the number that was taken. \(\displaystyle 58-11=47\).

This is a subtraction problem because we want to know how many games Jenny has left after she gives some to her friend. We take the total number of games that Jenny has, and then we subtract the number that she gave to her friend. \(\displaystyle 23-13=10\).

This is a subtraction problem because we want to know how many gifts she has left to open after she’s already opened some of her gifts. We take the total number of gifts she has, and then we subtract the number of gifts that she’s opened. \(\displaystyle 32-14=18\).

This is a subtraction problem because we want to find out how many of Matt’s invited friends were able to come to his party. We take the total number of people that were invited, and subtract the number of people that did not come. \(\displaystyle 28-7=21\). 

This is a subtraction problem because we want to know how many students in Ms. Smith’s class are in school today out of the total number of students that she has. We take the total number of students and subtract the number of students who are not in school today. \(\displaystyle 32-6=26\).

This is a subtraction problem because we want to know how many homework problems Joe will have left after he completes some of them. We take the total number of problems that he has and subtract the number that he plans to do tonight. \(\displaystyle 70-25=45\). 

This is a subtraction problem because we want to know how many birthday parties Lisa has left to attend this year. We take the total number of parties that she is invited to, and subtract the number of parties that she has already been to. \(\displaystyle 21-12=9\).