diff --git a/Exercises/day_1/datatypes.js b/Exercises/day_1/datatypes.js
new file mode 100644
index 0000000..0775fe3
--- /dev/null
+++ b/Exercises/day_1/datatypes.js
@@ -0,0 +1,4 @@
+typeof a_string;
+typeof a_boolean;
+typeof a_undefined;
+typeof a_null;
\ No newline at end of file
diff --git a/Exercises/day_1/index.html b/Exercises/day_1/index.html
new file mode 100644
index 0000000..74d989b
--- /dev/null
+++ b/Exercises/day_1/index.html
@@ -0,0 +1,14 @@
+
+
+
+
+
+
+ Day 1
+
+
+
+
+
+
+
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diff --git a/Exercises/day_1/script.js b/Exercises/day_1/script.js
new file mode 100644
index 0000000..631b76a
--- /dev/null
+++ b/Exercises/day_1/script.js
@@ -0,0 +1,6 @@
+//Comments can make code readable
+//Welcome to 30DayOfJavaScript
+/*
+comments can make code readable, easy to reuse and informative
+*/
+console.log("I am " + myAge + " years old\nYou are " + yourAge + " years old")
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diff --git a/Exercises/day_1/variable.js b/Exercises/day_1/variable.js
new file mode 100644
index 0000000..3d978cd
--- /dev/null
+++ b/Exercises/day_1/variable.js
@@ -0,0 +1,22 @@
+let a_string = "any string";
+let a_boolean = true;
+let a_undefined = undefined;
+let a_null = null;
+
+let a_string_1;
+let a_boolean_1;
+let a_undefined_1;
+let a_null_1;
+
+let first_name = "tran";
+let last_name = "hoang";
+let country = "viet nam";
+let age = 22;
+
+let first_name_1 = first_name,
+ last_name_1 = last_name,
+ country_1 = country,
+ age_1 = age;
+
+let myAge = 22;
+let yourAge = 30;
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