diff --git a/practice_projects/deleting_unneeded_files.py b/practice_projects/deleting_unneeded_files.py
new file mode 100644
index 0000000..1e2e390
--- /dev/null
+++ b/practice_projects/deleting_unneeded_files.py
@@ -0,0 +1,19 @@
+#!python3
+# deleting_unneeded_files.py - walks through a folder tree and searches for exceptionally large files or folders. say,
+# ones that have a file size of more than 100MB. Print these files with their absolute path to the screen.
+
+import os
+import shutil
+
+def deleting_large_files(fd, mega):
+    for foldername, subfolders, filenames in os.walk(fd):
+        for filename in filenames:
+            filepath = os.path.join(foldername, filename)
+            size = os.path.getsize(filepath)
+            size /= 1024 * 1024
+            if size > mega:
+                print(filepath)
+                #os.unlink(filepath)
+
+
+deleting_large_files("D:\\BaiduNetdiskDownload", 10)
diff --git a/practice_projects/filling_in_the_gaps.py b/practice_projects/filling_in_the_gaps.py
new file mode 100644
index 0000000..b88c8b1
--- /dev/null
+++ b/practice_projects/filling_in_the_gaps.py
@@ -0,0 +1,72 @@
+#!python3
+# filling_in_the_gaps.py - finds all files with a given prefix, such as
+# `spam001.txt`, spam002.txt, and so on, in a single folder and locates any
+# gaps in the numbering. Have the program rename all the later files to close
+# this gap.
+# write another program that can insert gaps into numbered files so that a new
+# file can be added.
+
+import os
+import shutil
+import re
+import random
+import pathlib
+
+
+def gengap(fd, prefix, n):
+    os.chdir(fd)
+    for f in os.listdir('.'):
+        os.unlink(f)
+
+    smp = random.sample(range(1, 100), n)
+    for idx in smp:
+        newfile = os.path.join('.', prefix + str(idx).zfill(3) + '.txt')
+        pathlib.Path(newfile).touch()
+
+
+def fillgap(fd, prefix):
+    os.chdir(fd)
+    reg = re.compile(r'^%s(\d+)' % prefix)
+    n = -1
+    sz = -1
+    for filename in os.listdir('.'):
+        mo = reg.search(filename)
+        if mo is not None:
+            if n == -1 and sz == -1:
+                n = int(mo.group(1))
+                sz = len(str(mo.group(1)))
+            else:
+                n += 1
+                newname = prefix + str(n).zfill(sz) +
+                os.path.splitext(filename)[1]
+                shutil.move(filename, newname)
+
+
+def insertgap(fd, prefix):
+    os.chdir(fd)
+    reg = re.compile(r'^%s(\d+)' % prefix)
+    for filename in os.listdir('.'):
+        mo = reg.search(filename)
+        if mo is not None:
+            n = int(mo.group(1))
+            sz = len(str(mo.group(1)))
+            newfile = os.path.join('.', prefix + str(n).zfill(sz) +
+                                   os.path.splitext(filename)[1])
+            while os.path.exists(newfile):
+                n += 1
+                newfile = os.path.join('.', prefix + str(n).zfill(sz) +
+                                       os.path.splitext(filename)[1])
+            pathlib.Path(newfile).touch()
+            break
+
+
+curpath = os.getcwd()
+
+# os.chdir(curpath)
+# gengap('test', 'spam', 9)
+
+# os.chdir(curpath)
+# insertgap('test', 'spam')
+
+os.chdir(curpath)
+fillgap('test', 'spam')
diff --git a/practice_projects/selective_copy.py b/practice_projects/selective_copy.py
new file mode 100644
index 0000000..efe574a
--- /dev/null
+++ b/practice_projects/selective_copy.py
@@ -0,0 +1,28 @@
+#!python3
+# selective_copy.py - walks through a folder tree and searches for files with a
+# certain file extension (such as .pdf or .jpg). Copy these files from whatever
+# location they are in to a new folder.
+
+import os
+import shutil
+
+
+def selective_copy(flr, ext, new_flr):
+    if not os.path.exists(new_flr):
+        os.mkdir(new_flr)
+    base = os.path.basename(new_flr)
+
+    for foldername, subfolders, filenames in os.walk(flr):
+        new_base = os.path.basename(foldername)
+        if base == new_base:
+            continue
+
+        for filename in filenames:
+            if filename.endswith(ext):
+                filepath = os.path.join(foldername, filename)
+                new_filepath = os.path.join(new_flr, filename)
+                shutil.move(filepath, new_filepath)
+
+
+selective_copy("C:\\Users\\pezy\\Downloads", ('.exe', '.msi'),
+               "C:\\Users\\pezy\\Downloads\\Software")
diff --git a/practice_projects/test/spam016.txt b/practice_projects/test/spam016.txt
new file mode 100644
index 0000000..e69de29
diff --git a/practice_projects/test/spam017.txt b/practice_projects/test/spam017.txt
new file mode 100644
index 0000000..e69de29
diff --git a/practice_projects/test/spam018.txt b/practice_projects/test/spam018.txt
new file mode 100644
index 0000000..e69de29
diff --git a/practice_projects/test/spam019.txt b/practice_projects/test/spam019.txt
new file mode 100644
index 0000000..e69de29
diff --git a/practice_projects/test/spam020.txt b/practice_projects/test/spam020.txt
new file mode 100644
index 0000000..e69de29
diff --git a/practice_projects/test/spam021.txt b/practice_projects/test/spam021.txt
new file mode 100644
index 0000000..e69de29
diff --git a/practice_projects/test/spam022.txt b/practice_projects/test/spam022.txt
new file mode 100644
index 0000000..e69de29
diff --git a/practice_projects/test/spam023.txt b/practice_projects/test/spam023.txt
new file mode 100644
index 0000000..e69de29
diff --git a/practice_projects/test/spam024.txt b/practice_projects/test/spam024.txt
new file mode 100644
index 0000000..e69de29
diff --git a/practice_projects/test/spam025.txt b/practice_projects/test/spam025.txt
new file mode 100644
index 0000000..e69de29
diff --git a/practice_questions/README.md b/practice_questions/README.md
index 482d495..e01f0d0 100644
--- a/practice_questions/README.md
+++ b/practice_questions/README.md
@@ -8,3 +8,4 @@
 - [Chapter 6 – Manipulating Strings](ch06/README.md)
 - [Chapter 7 – Pattern Matching with Regular Expressions](ch07/README.md)
 - [Chapter 8 – Reading and Writing Files](ch08/README.md)
+- [Chapter 9 – Organizing Files](ch09/README.md)
diff --git a/practice_questions/ch09/README.md b/practice_questions/ch09/README.md
new file mode 100644
index 0000000..bf6a906
--- /dev/null
+++ b/practice_questions/ch09/README.md
@@ -0,0 +1,17 @@
+# Chapter 9 – Organizing Files
+
+> Q: 1. What is the difference between `shutil.copy()` and `shutil.copytree()`?
+
+`shutil.copy()` copies the file, `shutil.copytree()` copies the directory.
+
+> Q: 2. What function is used to rename files?
+
+`shutil.move()`
+
+> Q: 3. What is the difference between the delete functions in the `send2trash` and `shutil` modules?
+
+`send2trash` will move file to recycle bin, while `shutil` functions will permanently delete files and folders.
+
+> Q: 4. `ZipFile` objects have a `close()` method just like `File` objects’ `close()` method. What `ZipFile` method is equivalent to `File` objects’ `open()` method?
+
+`zipfile.ZipFile()`.
\ No newline at end of file