diff --git a/3_linear_regression/linear_regression.ipynb b/3_linear_regression/linear_regression.ipynb
index c4af66a..cf97bde 100644
--- a/3_linear_regression/linear_regression.ipynb
+++ b/3_linear_regression/linear_regression.ipynb
@@ -441,8 +441,9 @@
    },
    "outputs": [],
    "source": [
+    "shapeWithNa = df.shape\n",
     "assert df.duplicated(['id']).sum() == 0\n",
-    "assert df.shape == (11060, 37)"
+    "assert shapeWithNa == (11060, 37)"
    ]
   },
   {
@@ -489,6 +490,7 @@
    },
    "outputs": [],
    "source": [
+    "naColumnsCount = df.isna().sum().max()\n",
     "df.isna().sum()"
    ]
   },
@@ -558,7 +560,9 @@
    },
    "outputs": [],
    "source": [
-    "assert df.isna().sum().sum() == 0"
+    "assert df.isna().sum().sum() == 0\n",
+    "shapeWithoutNa = df.shape\n",
+    "assert tuple(np.subtract(shapeWithNa, shapeWithoutNa)) == (naColumnsCount, 2) # 2 - dropped columns count: ['id', 'date']"
    ]
   },
   {