Suppose $\backslash (\backslash$mathrm$\{$f$\}(\backslash$mathrm$\{$x$\})\backslash )$ represents the total number of children that have a symptom, and $\backslash ($ x $\backslash )$ is the number of days since the first case.

Step $1$ of $2$: Interpret the meaning of $\backslash ($ f$(33)=100\backslash ).$

Answer$100$ is the rate of change in children who have a symptom after $33$ days.

$100$ is the average change in the number of children who have a symptom between the first day and $33$ days later.

After $33$ days $100$ children have a symptom.

$100$ is the total change between the first day and $33$ days later.