We discussed the standard normal distribution and tried hands-on practice 3 Q1, 2, 3 and 5. Next, we discussed linear combination of normal distributions. It is very important for students to understand that in normal distributions, $x_1+x_2 \neq2x$. We discussed the ways to identify when we are adding and when we are multiplying. We also discussed the properties of mean $E(x)$ and variance $Var(x)$. Lastly, we finished up the lesson with the kind of question that requires us to change the unit.