diff --git a/College/AU 26/MATH 224 (Multivar)/Class 10-2.md b/College/AU 26/MATH 224 (Multivar)/Class 10-2.md
index ae7ca08..184185e 100644
--- a/College/AU 26/MATH 224 (Multivar)/Class 10-2.md	
+++ b/College/AU 26/MATH 224 (Multivar)/Class 10-2.md	
@@ -11,4 +11,6 @@
 	- defining region
 		- $$R=[a,b] \times [c,d]$$
 		- x values are between $a$ and $b$ , y values are between $c$ and $d$
+	- slice up solid into equations that can be integrated with one variable
+	- $$\int \int_{[a,b] \times [c,d]} f(x,y) dA = \int^b_{a} \int^d_{c}f(x,y)dy dx$$
 	- 
\ No newline at end of file