diff --git a/study/introduction-to-probability-statistics-and-random-processes/.ipynb_checkpoints/ch1-checkpoint.ipynb b/study/001_introduction-to-probability-statistics-and-random-processes/.ipynb_checkpoints/ch1-checkpoint.ipynb similarity index 100% rename from study/introduction-to-probability-statistics-and-random-processes/.ipynb_checkpoints/ch1-checkpoint.ipynb rename to study/001_introduction-to-probability-statistics-and-random-processes/.ipynb_checkpoints/ch1-checkpoint.ipynb diff --git a/study/introduction-to-probability-statistics-and-random-processes/README.md b/study/001_introduction-to-probability-statistics-and-random-processes/README.md similarity index 100% rename from study/introduction-to-probability-statistics-and-random-processes/README.md rename to study/001_introduction-to-probability-statistics-and-random-processes/README.md diff --git a/study/introduction-to-probability-statistics-and-random-processes/notebooks/ch1.ipynb b/study/001_introduction-to-probability-statistics-and-random-processes/notebooks/ch1.ipynb similarity index 100% rename from study/introduction-to-probability-statistics-and-random-processes/notebooks/ch1.ipynb rename to study/001_introduction-to-probability-statistics-and-random-processes/notebooks/ch1.ipynb diff --git a/study/introduction-to-probability-statistics-and-random-processes/textbooks/Introduction to Probability, Statistics, and Random Processes - Hossein Pishro-Nik.pdf b/study/001_introduction-to-probability-statistics-and-random-processes/textbooks/Introduction to Probability, Statistics, and Random Processes - Hossein Pishro-Nik.pdf similarity index 100% rename from study/introduction-to-probability-statistics-and-random-processes/textbooks/Introduction to Probability, Statistics, and Random Processes - Hossein Pishro-Nik.pdf rename to study/001_introduction-to-probability-statistics-and-random-processes/textbooks/Introduction to Probability, Statistics, and Random Processes - Hossein Pishro-Nik.pdf diff --git a/study/introduction-to-probability-statistics-and-random-processes/textbooks/Introduction to Probability, Statistics, and Random Processes - Hossein Pishro-Nik_SOLUTIONS.pdf b/study/001_introduction-to-probability-statistics-and-random-processes/textbooks/Introduction to Probability, Statistics, and Random Processes - Hossein Pishro-Nik_SOLUTIONS.pdf similarity index 100% rename from study/introduction-to-probability-statistics-and-random-processes/textbooks/Introduction to Probability, Statistics, and Random Processes - Hossein Pishro-Nik_SOLUTIONS.pdf rename to study/001_introduction-to-probability-statistics-and-random-processes/textbooks/Introduction to Probability, Statistics, and Random Processes - Hossein Pishro-Nik_SOLUTIONS.pdf