diff --git a/guide/english/mathematics/3-by-3-determinants/index.md b/guide/english/mathematics/3-by-3-determinants/index.md
index a0207612d8..0dff4ba323 100644
--- a/guide/english/mathematics/3-by-3-determinants/index.md
+++ b/guide/english/mathematics/3-by-3-determinants/index.md
@@ -68,7 +68,7 @@ For example, consider the following matrix, which we will call B:
 <pre><em>det(B) = (-41) - 100 - 90 = -231</em></pre>
 
 ### Method 2 - Sarrus's Rule
-This method it similar to 2 by 2 determinants, and based on opertations with diagonals
+This method is similar to 2 by 2 determinants, and based on opertations with diagonals
 Again, consider the following matrix, which we will call A:
 
 <table>