diff --git a/Moonjonghoo/array/create_stars_at_intersections.js b/Moonjonghoo/array/create_stars_at_intersections.js
new file mode 100644
index 0000000..81bd3d1
--- /dev/null
+++ b/Moonjonghoo/array/create_stars_at_intersections.js
@@ -0,0 +1,4 @@
+function solution(line) {
+  var answer = [];
+  return answer;
+}
diff --git a/Moonjonghoo/array/divisible_number_array.js b/Moonjonghoo/array/divisible_number_array.js
new file mode 100644
index 0000000..767fcbe
--- /dev/null
+++ b/Moonjonghoo/array/divisible_number_array.js
@@ -0,0 +1,17 @@
+function solution(arr, divisor) {
+  var answer = [];
+  for (let i = 0; i < arr.length; i++) {
+    if (arr[i] % divisor === 0) {
+      answer.push(arr[i]);
+    }
+  }
+  if (answer.length === 0) {
+    answer = [-1];
+  }
+
+  answer.sort(function (a, b) {
+    return a - b;
+  });
+
+  return answer;
+}
diff --git a/Moonjonghoo/array/duplicate_number_count.js b/Moonjonghoo/array/duplicate_number_count.js
new file mode 100644
index 0000000..615f571
--- /dev/null
+++ b/Moonjonghoo/array/duplicate_number_count.js
@@ -0,0 +1,9 @@
+function solution(array, n) {
+  var answer = 0;
+  for (let i = 0; i < array.length; i++) {
+    if (array[i] === n) {
+      answer++;
+    }
+  }
+  return answer;
+}
diff --git a/Moonjonghoo/array/length_of_an_array_element.js b/Moonjonghoo/array/length_of_an_array_element.js
new file mode 100644
index 0000000..4750486
--- /dev/null
+++ b/Moonjonghoo/array/length_of_an_array_element.js
@@ -0,0 +1,9 @@
+function solution(strlist) {
+  var answer = [];
+  for (let i = 0; i < strlist.length; i++) {
+    answer.push(strlist[i].length);
+  }
+  return answer;
+}
+
+console.log(solution(["We", "are", "the", "world!"]));
diff --git a/Moonjonghoo/array/matrix_addition.js b/Moonjonghoo/array/matrix_addition.js
new file mode 100644
index 0000000..f99ea27
--- /dev/null
+++ b/Moonjonghoo/array/matrix_addition.js
@@ -0,0 +1,23 @@
+function solution(arr1, arr2) {
+  var answer = [];
+  for (let i = 0; i < arr1.length; i++) {
+    let minarr = [];
+    for (let j = 0; j < arr1[i].length; j++) {
+      minarr.push(arr1[i][j] + arr2[i][j]);
+    }
+    answer.push(minarr);
+  }
+  return answer;
+}
+console.log(
+  solution(
+    [
+      [1, 2],
+      [2, 3],
+    ],
+    [
+      [3, 4],
+      [5, 6],
+    ]
+  )
+);
diff --git a/Moonjonghoo/array/matrix_multiplication.js b/Moonjonghoo/array/matrix_multiplication.js
new file mode 100644
index 0000000..85c5ed8
--- /dev/null
+++ b/Moonjonghoo/array/matrix_multiplication.js
@@ -0,0 +1,17 @@
+function solution(arr1, arr2) {
+  const newArr = [];
+
+  for (let i = 0; i < arr1.length; i++) {
+    let result = [];
+    for (let j = 0; j < arr2[0].length; j++) {
+      let elem = 0;
+      for (let k = 0; k < arr2.length; k++) {
+        // arr1[0].length도 가능.
+        elem += arr1[i][k] * arr2[k][j];
+      }
+      result.push(elem);
+    }
+    newArr.push(result);
+  }
+  return newArr;
+}
diff --git a/Moonjonghoo/array/remove_smallest_number.js b/Moonjonghoo/array/remove_smallest_number.js
new file mode 100644
index 0000000..5a78728
--- /dev/null
+++ b/Moonjonghoo/array/remove_smallest_number.js
@@ -0,0 +1,16 @@
+function solution(arr) {
+  var answer = [];
+  if (arr.length === 1) {
+    answer = [-1];
+  } else {
+    let min = Math.min(...arr);
+    for (let i = 0; i < arr.length; i++) {
+      if (arr[i] !== min) {
+        answer.push(arr[i]);
+      }
+    }
+  }
+  return answer;
+}
+
+solution([4, 3, 2, 1]);
diff --git a/Moonjonghoo/array/rotate_an_array.js b/Moonjonghoo/array/rotate_an_array.js
new file mode 100644
index 0000000..b11c393
--- /dev/null
+++ b/Moonjonghoo/array/rotate_an_array.js
@@ -0,0 +1,20 @@
+function solution(numbers, direction) {
+  var answer = [];
+  //배열내부에 위치를 변경시키는 방법
+  for (let i = 0; i < numbers.length; i++) {
+    if (direction === "right") {
+      let start = numbers[numbers.length - 1];
+      answer = numbers.slice(0, numbers.length - 1);
+      answer.unshift(start);
+    }
+    if (direction === "left") {
+      let start = numbers[0];
+      answer = numbers.slice(1, numbers.length);
+      answer.push(start);
+    }
+  }
+
+  return answer;
+}
+
+console.log(solution([1, 2, 3], "right"));
diff --git a/Moonjonghoo/array/slice_an_array.js b/Moonjonghoo/array/slice_an_array.js
new file mode 100644
index 0000000..8b1e639
--- /dev/null
+++ b/Moonjonghoo/array/slice_an_array.js
@@ -0,0 +1,7 @@
+function solution(numbers, num1, num2) {
+  var answer = [];
+  answer = numbers.slice(num1, num2 + 1);
+  return answer;
+}
+
+console.log(solution([1, 2, 3, 4, 5], 1, 3));