diff --git a/build.py b/build.py
index 35cdd2a..dcda46c 100644
--- a/build.py
+++ b/build.py
@@ -1,25 +1,32 @@
+import pandas as pd
+
 def get_categorical_variables(df):
-    return []
+    categorical_data = list(df[['country', 'new_user', 'source', 'converted']])
+    return categorical_data
 
 
 def get_numerical_variables(df):
-    return []
+    numerical_data = list(df[['age', 'total_pages_visited']])
+    return numerical_data
 
 
 def get_numerical_variables_percentile(df):
-    pass
+    return df.describe()
 
 
 def get_categorical_variables_modes(df):
-    pass
-
+    return df[get_categorical_variables(df)].mode()
 
 def get_missing_values_count(df):
-    pass
+    return pd.DataFrame(df.isnull().sum())
 
 
 def plot_histogram_with_numerical_values(df):
-    pass
+    plt.hist(df['age'], color='r', bins=50)
+    plt.hist(df['total_pages_visited'], color='b', bins=50)
+    plt.xlabel('age')
+    plt.ylabel('total_pages_visited')
+    plt.show()
 
 
 def plot_facet_box(df):
diff --git a/build.pyc b/build.pyc
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diff --git a/tests/__init__.pyc b/tests/__init__.pyc
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index 0000000..8d432fd
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diff --git a/tests/test_get_categorical_variables.pyc b/tests/test_get_categorical_variables.pyc
new file mode 100644
index 0000000..9d085d7
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