diff --git a/problems/1-two-sum/main.rb b/problems/0001-two-sum/main.rb similarity index 100% rename from problems/1-two-sum/main.rb rename to problems/0001-two-sum/main.rb diff --git a/problems/1-two-sum/readme.md b/problems/0001-two-sum/readme.md similarity index 100% rename from problems/1-two-sum/readme.md rename to problems/0001-two-sum/readme.md diff --git a/problems/1-two-sum/test.rb b/problems/0001-two-sum/test.rb similarity index 100% rename from problems/1-two-sum/test.rb rename to problems/0001-two-sum/test.rb diff --git a/problems/2-add-two-numbers/main.rb b/problems/0002-add-two-numbers/main.rb similarity index 100% rename from problems/2-add-two-numbers/main.rb rename to problems/0002-add-two-numbers/main.rb diff --git a/problems/2-add-two-numbers/readme.md b/problems/0002-add-two-numbers/readme.md similarity index 100% rename from problems/2-add-two-numbers/readme.md rename to problems/0002-add-two-numbers/readme.md diff --git a/problems/2-add-two-numbers/test.rb 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problems/0008-string-to-integer/main.rb diff --git a/problems/8-string-to-integer/test.rb b/problems/0008-string-to-integer/test.rb similarity index 100% rename from problems/8-string-to-integer/test.rb rename to problems/0008-string-to-integer/test.rb diff --git a/problems/9-palindrome-number/main.rb b/problems/0009-palindrome-number/main.rb similarity index 100% rename from problems/9-palindrome-number/main.rb rename to problems/0009-palindrome-number/main.rb diff --git a/problems/9-palindrome-number/test.rb b/problems/0009-palindrome-number/test.rb similarity index 100% rename from problems/9-palindrome-number/test.rb rename to problems/0009-palindrome-number/test.rb diff --git a/problems/12-integer-to-roman/main.rb b/problems/0012-integer-to-roman/main.rb similarity index 100% rename from problems/12-integer-to-roman/main.rb rename to problems/0012-integer-to-roman/main.rb diff --git a/problems/12-integer-to-roman/test.rb b/problems/0012-integer-to-roman/test.rb similarity index 100% rename from problems/12-integer-to-roman/test.rb rename to problems/0012-integer-to-roman/test.rb diff --git a/problems/14-longest-common-prefix/main.rb b/problems/0014-longest-common-prefix/main.rb similarity index 100% rename from problems/14-longest-common-prefix/main.rb rename to problems/0014-longest-common-prefix/main.rb diff --git a/problems/14-longest-common-prefix/test.rb b/problems/0014-longest-common-prefix/test.rb similarity index 100% rename from problems/14-longest-common-prefix/test.rb rename to problems/0014-longest-common-prefix/test.rb diff --git a/problems/22-generate-parentheses/main.rb b/problems/0022-generate-parentheses/main.rb similarity index 100% rename from problems/22-generate-parentheses/main.rb rename to problems/0022-generate-parentheses/main.rb diff --git a/problems/22-generate-parentheses/readme.md b/problems/0022-generate-parentheses/readme.md similarity index 100% rename from problems/22-generate-parentheses/readme.md rename to problems/0022-generate-parentheses/readme.md diff --git a/problems/22-generate-parentheses/test.rb b/problems/0022-generate-parentheses/test.rb similarity index 100% rename from problems/22-generate-parentheses/test.rb rename to problems/0022-generate-parentheses/test.rb diff --git a/problems/36-valid-sudoku/main.rb b/problems/0036-valid-sudoku/main.rb similarity index 100% rename from problems/36-valid-sudoku/main.rb rename to problems/0036-valid-sudoku/main.rb diff --git a/problems/36-valid-sudoku/test.rb b/problems/0036-valid-sudoku/test.rb similarity index 100% rename from problems/36-valid-sudoku/test.rb rename to problems/0036-valid-sudoku/test.rb diff --git a/problems/37-sudoku-solver/main.rb b/problems/0037-sudoku-solver/main.rb similarity index 100% rename from problems/37-sudoku-solver/main.rb rename to problems/0037-sudoku-solver/main.rb diff --git a/problems/37-sudoku-solver/test.rb b/problems/0037-sudoku-solver/test.rb similarity index 100% rename from problems/37-sudoku-solver/test.rb rename to problems/0037-sudoku-solver/test.rb diff --git a/problems/193-valid-phone-numbers/file.txt b/problems/0193-valid-phone-numbers/file.txt similarity index 100% rename from problems/193-valid-phone-numbers/file.txt rename to problems/0193-valid-phone-numbers/file.txt diff --git a/problems/193-valid-phone-numbers/main.sh b/problems/0193-valid-phone-numbers/main.sh similarity index 100% rename from problems/193-valid-phone-numbers/main.sh rename to problems/0193-valid-phone-numbers/main.sh diff --git a/problems/193-valid-phone-numbers/readme.md b/problems/0193-valid-phone-numbers/readme.md similarity index 100% rename from problems/193-valid-phone-numbers/readme.md rename to problems/0193-valid-phone-numbers/readme.md diff --git a/problems/223-rectangle-area/main.rb b/problems/0223-rectangle-area/main.rb similarity index 100% rename from problems/223-rectangle-area/main.rb rename to problems/0223-rectangle-area/main.rb diff --git a/problems/223-rectangle-area/readme.md b/problems/0223-rectangle-area/readme.md similarity index 100% rename from problems/223-rectangle-area/readme.md rename to problems/0223-rectangle-area/readme.md diff --git a/problems/223-rectangle-area/test.rb b/problems/0223-rectangle-area/test.rb similarity index 100% rename from problems/223-rectangle-area/test.rb rename to problems/0223-rectangle-area/test.rb