diff --git a/04_data_structures/structures/example_01/main.go b/04_data_structures/01-structures/example_01/main.go similarity index 100% rename from 04_data_structures/structures/example_01/main.go rename to 04_data_structures/01-structures/example_01/main.go diff --git a/04_data_structures/structures/example_02/main.go b/04_data_structures/01-structures/example_02/main.go similarity index 100% rename from 04_data_structures/structures/example_02/main.go rename to 04_data_structures/01-structures/example_02/main.go diff --git a/04_data_structures/structures/example_03/main.go b/04_data_structures/01-structures/example_03/main.go similarity index 100% rename from 04_data_structures/structures/example_03/main.go rename to 04_data_structures/01-structures/example_03/main.go diff --git a/04_data_structures/structures/example_04/main.go b/04_data_structures/01-structures/example_04/main.go similarity index 100% rename from 04_data_structures/structures/example_04/main.go rename to 04_data_structures/01-structures/example_04/main.go diff --git a/04_data_structures/structures/example_05/main.go b/04_data_structures/01-structures/example_05/main.go similarity index 100% rename from 04_data_structures/structures/example_05/main.go rename to 04_data_structures/01-structures/example_05/main.go diff --git a/04_data_structures/methods/example_01/main.go b/04_data_structures/02-methods/example_01/main.go similarity index 100% rename from 04_data_structures/methods/example_01/main.go rename to 04_data_structures/02-methods/example_01/main.go diff --git a/04_data_structures/methods/example_02/main.go b/04_data_structures/02-methods/example_02/main.go similarity index 100% rename from 04_data_structures/methods/example_02/main.go rename to 04_data_structures/02-methods/example_02/main.go diff --git a/04_data_structures/methods/example_03/main.go b/04_data_structures/02-methods/example_03/main.go similarity index 100% rename from 04_data_structures/methods/example_03/main.go rename to 04_data_structures/02-methods/example_03/main.go diff --git a/04_data_structures/interfaces/example_01/main.go b/04_data_structures/03-interfaces/example_01/main.go similarity index 100% rename from 04_data_structures/interfaces/example_01/main.go rename to 04_data_structures/03-interfaces/example_01/main.go diff --git a/04_data_structures/interfaces/example_01a/main.go b/04_data_structures/03-interfaces/example_01a/main.go similarity index 100% rename from 04_data_structures/interfaces/example_01a/main.go rename to 04_data_structures/03-interfaces/example_01a/main.go diff --git a/04_data_structures/interfaces/example_02/main.go b/04_data_structures/03-interfaces/example_02/main.go similarity index 100% rename from 04_data_structures/interfaces/example_02/main.go rename to 04_data_structures/03-interfaces/example_02/main.go diff --git a/04_data_structures/interfaces/example_03/main.go b/04_data_structures/03-interfaces/example_03/main.go similarity index 100% rename from 04_data_structures/interfaces/example_03/main.go rename to 04_data_structures/03-interfaces/example_03/main.go diff --git a/05_reflection/reflect_type/example_01/main.go b/05_reflection/01-reflect_type/example_01/main.go similarity index 100% rename from 05_reflection/reflect_type/example_01/main.go rename to 05_reflection/01-reflect_type/example_01/main.go diff --git a/05_reflection/reflect_type/example_02/main.go b/05_reflection/01-reflect_type/example_02/main.go similarity index 100% rename from 05_reflection/reflect_type/example_02/main.go rename to 05_reflection/01-reflect_type/example_02/main.go diff --git a/05_reflection/reflect_type/example_03/main.go b/05_reflection/01-reflect_type/example_03/main.go similarity index 100% rename from 05_reflection/reflect_type/example_03/main.go rename to 05_reflection/01-reflect_type/example_03/main.go diff --git a/05_reflection/reflect_type/example_04/main.go b/05_reflection/01-reflect_type/example_04/main.go similarity index 100% rename from 05_reflection/reflect_type/example_04/main.go rename to 05_reflection/01-reflect_type/example_04/main.go diff --git a/05_reflection/reflect_value/example_01/main.go b/05_reflection/02-reflect_value/example_01/main.go similarity index 100% rename from 05_reflection/reflect_value/example_01/main.go rename to 05_reflection/02-reflect_value/example_01/main.go diff --git a/05_reflection/reflect_value/example_02/main.go b/05_reflection/02-reflect_value/example_02/main.go similarity index 100% rename from 05_reflection/reflect_value/example_02/main.go rename to 05_reflection/02-reflect_value/example_02/main.go diff --git a/05_reflection/reflect_value/example_03/main.go b/05_reflection/02-reflect_value/example_03/main.go similarity index 100% rename from 05_reflection/reflect_value/example_03/main.go rename to 05_reflection/02-reflect_value/example_03/main.go diff --git a/05_reflection/reflect_value/example_04/main.go b/05_reflection/02-reflect_value/example_04/main.go similarity index 100% rename from 05_reflection/reflect_value/example_04/main.go rename to 05_reflection/02-reflect_value/example_04/main.go diff --git a/05_reflection/reflect_value/example_05/main.go b/05_reflection/02-reflect_value/example_05/main.go similarity index 100% rename from 05_reflection/reflect_value/example_05/main.go rename to 05_reflection/02-reflect_value/example_05/main.go diff --git a/05_reflection/functions/example_01/main.go b/05_reflection/03-functions/example_01/main.go similarity index 100% rename from 05_reflection/functions/example_01/main.go rename to 05_reflection/03-functions/example_01/main.go diff --git a/05_reflection/functions/example_02/main.go b/05_reflection/03-functions/example_02/main.go similarity index 100% rename from 05_reflection/functions/example_02/main.go rename to 05_reflection/03-functions/example_02/main.go diff --git a/05_reflection/tags/example_01/main.go b/05_reflection/04-tags/example_01/main.go similarity index 100% rename from 05_reflection/tags/example_01/main.go rename to 05_reflection/04-tags/example_01/main.go diff --git a/05_reflection/tests/main.go b/05_reflection/05-tests/main.go similarity index 100% rename from 05_reflection/tests/main.go rename to 05_reflection/05-tests/main.go diff --git a/06_concurrency/goroutines/example01/main.go b/06_concurrency/01-goroutines/example01/main.go similarity index 100% rename from 06_concurrency/goroutines/example01/main.go rename to 06_concurrency/01-goroutines/example01/main.go diff --git a/06_concurrency/goroutines/example02/main.go b/06_concurrency/01-goroutines/example02/main.go similarity index 100% rename from 06_concurrency/goroutines/example02/main.go rename to 06_concurrency/01-goroutines/example02/main.go diff --git a/06_concurrency/channels/example_01/main.go b/06_concurrency/02-channels/example_01/main.go similarity index 100% rename from 06_concurrency/channels/example_01/main.go rename to 06_concurrency/02-channels/example_01/main.go diff --git a/06_concurrency/channels/example_01a/main.go b/06_concurrency/02-channels/example_01a/main.go similarity index 100% rename from 06_concurrency/channels/example_01a/main.go rename to 06_concurrency/02-channels/example_01a/main.go diff --git a/06_concurrency/channels/example_02/main.go b/06_concurrency/02-channels/example_02/main.go similarity index 100% rename from 06_concurrency/channels/example_02/main.go rename to 06_concurrency/02-channels/example_02/main.go diff --git a/06_concurrency/channels/example_03/main.go b/06_concurrency/02-channels/example_03/main.go similarity index 100% rename from 06_concurrency/channels/example_03/main.go rename to 06_concurrency/02-channels/example_03/main.go diff --git a/06_concurrency/channels/example_04/main.go b/06_concurrency/02-channels/example_04/main.go similarity index 100% rename from 06_concurrency/channels/example_04/main.go rename to 06_concurrency/02-channels/example_04/main.go diff --git a/06_concurrency/channels/example_05/main.go b/06_concurrency/02-channels/example_05/main.go similarity index 100% rename from 06_concurrency/channels/example_05/main.go rename to 06_concurrency/02-channels/example_05/main.go diff --git a/06_concurrency/select/example_01a/main.go b/06_concurrency/03-select/example_01a/main.go similarity index 100% rename from 06_concurrency/select/example_01a/main.go rename to 06_concurrency/03-select/example_01a/main.go diff --git a/06_concurrency/select/example_01b/main.go b/06_concurrency/03-select/example_01b/main.go similarity index 100% rename from 06_concurrency/select/example_01b/main.go rename to 06_concurrency/03-select/example_01b/main.go diff --git a/06_concurrency/select/example_02/main.go b/06_concurrency/03-select/example_02/main.go similarity index 100% rename from 06_concurrency/select/example_02/main.go rename to 06_concurrency/03-select/example_02/main.go diff --git a/06_concurrency/waitgroup/example_01/main.go b/06_concurrency/04-waitgroup/example_01/main.go similarity index 100% rename from 06_concurrency/waitgroup/example_01/main.go rename to 06_concurrency/04-waitgroup/example_01/main.go diff --git a/06_concurrency/timers_tickers_timeouts/example_01/main.go b/06_concurrency/05-timers_tickers_timeouts/example_01/main.go similarity index 100% rename from 06_concurrency/timers_tickers_timeouts/example_01/main.go rename to 06_concurrency/05-timers_tickers_timeouts/example_01/main.go diff --git a/06_concurrency/timers_tickers_timeouts/example_02/main.go b/06_concurrency/05-timers_tickers_timeouts/example_02/main.go similarity index 100% rename from 06_concurrency/timers_tickers_timeouts/example_02/main.go rename to 06_concurrency/05-timers_tickers_timeouts/example_02/main.go diff --git a/06_concurrency/context/parents/main.go b/06_concurrency/06-context/parents/main.go similarity index 100% rename from 06_concurrency/context/parents/main.go rename to 06_concurrency/06-context/parents/main.go diff --git a/06_concurrency/context/with_cancel/main.go b/06_concurrency/06-context/with_cancel/main.go similarity index 100% rename from 06_concurrency/context/with_cancel/main.go rename to 06_concurrency/06-context/with_cancel/main.go diff --git a/06_concurrency/context/with_deadline/main.go b/06_concurrency/06-context/with_deadline/main.go similarity index 100% rename from 06_concurrency/context/with_deadline/main.go rename to 06_concurrency/06-context/with_deadline/main.go diff --git a/06_concurrency/context/with_timeout/main.go b/06_concurrency/06-context/with_timeout/main.go similarity index 100% rename from 06_concurrency/context/with_timeout/main.go rename to 06_concurrency/06-context/with_timeout/main.go diff --git a/06_concurrency/context/with_value/main.go b/06_concurrency/06-context/with_value/main.go similarity index 100% rename from 06_concurrency/context/with_value/main.go rename to 06_concurrency/06-context/with_value/main.go diff --git a/06_concurrency/once/example_01/main.go b/06_concurrency/07-once/example_01/main.go similarity index 100% rename from 06_concurrency/once/example_01/main.go rename to 06_concurrency/07-once/example_01/main.go diff --git a/06_concurrency/mutex/example_01/main.go b/06_concurrency/08-mutex/example_01/main.go similarity index 100% rename from 06_concurrency/mutex/example_01/main.go rename to 06_concurrency/08-mutex/example_01/main.go diff --git a/06_concurrency/atomics/example_01/main.go b/06_concurrency/09-atomics/example_01/main.go similarity index 100% rename from 06_concurrency/atomics/example_01/main.go rename to 06_concurrency/09-atomics/example_01/main.go diff --git a/06_concurrency/atomics/example_02/main.go b/06_concurrency/09-atomics/example_02/main.go similarity index 100% rename from 06_concurrency/atomics/example_02/main.go rename to 06_concurrency/09-atomics/example_02/main.go