diff --git a/docs/1b/ece106.md b/docs/1b/ece106.md
index d564f7b..e2629d3 100644
--- a/docs/1b/ece106.md
+++ b/docs/1b/ece106.md
@@ -214,3 +214,10 @@ $$dQ=\rho_s dS$$
 
 !!! example
     A rod of uniform charge density and length $L$ has a charge density of $p_\ell=\frac{Q}{L}$.
+
+1. Determine the formula for the charge density $\rho$
+2. Choose an origin and coordinate system (along the axes of the object when possible)
+3. Choose an arbitrary point $A$ on the charge
+4. Create a right-angle triangle with $A$, the desired point, and usually the origin
+5. Attempt to find symmetry
+6. Solve
diff --git a/docs/1b/ece124.md b/docs/1b/ece124.md
index 195826f..30ce76d 100644
--- a/docs/1b/ece124.md
+++ b/docs/1b/ece124.md
@@ -266,6 +266,10 @@ The 1-bit Gray code is $0, 1$. To convert an $n$-bit Gray code to an $n+1$-bit G
 
 Sorting truth table inputs in the order of the Gray code makes optimisation easier to do.
 
+A **"don't care"** is represented by a $d$ in truth tables. It is used for optimisation if the state of that output doesn't matter, and can be treated as a one or a zero as desired.
+
+It can be more efficient to optimise two different functions differently such that they are more optimised when combined.
+
 ### K-maps
 
 Karnaugh maps are an alternate representation of truth tables arranged by the Gray code.