diff --git a/lessons/04_classification.ipynb b/lessons/04_classification.ipynb
index 5b7b0b7..a59ae5c 100644
--- a/lessons/04_classification.ipynb
+++ b/lessons/04_classification.ipynb
@@ -361,9 +361,9 @@
     "1. **Precision**: \n",
     "$$\\frac{\\sum{\\text{True Positives}}}{\\sum{\\text{Predicted Positives}}}$$\n",
     "2. **Recall** (or **Sensitivity**): \n",
-    "$$\\frac{\\sum{\\text{True Positives}}}{\\sum{\\text{Condition Positives}}}$$ \n",
+    "$$\\frac{\\sum{\\text{True Positives}}}{\\sum{\\text{Actual Positives}}}$$ \n",
     "3. **Specificity** (like recall for negative examples): \n",
-    "$$\\frac{\\sum{\\text{True Negatives}}}{\\sum{\\text{Condition Negatives}}}$$\n"
+    "$$\\frac{\\sum{\\text{True Negatives}}}{\\sum{\\text{Actual Negatives}}}$$\n"
    ]
   },
   {