diff --git "a/oh-chaeyeon/2\354\243\274\354\260\250_\354\212\244\355\203\235/Control_Z.js" "b/oh-chaeyeon/2\354\243\274\354\260\250_\354\212\244\355\203\235/Control_Z.js"
new file mode 100644
index 0000000..4086d55
--- /dev/null
+++ "b/oh-chaeyeon/2\354\243\274\354\260\250_\354\212\244\355\203\235/Control_Z.js"
@@ -0,0 +1,14 @@
+function solution(s) {
+  const elements = s.split(" ");
+  let total = 0;
+
+  for (let i = 0; i < elements.length; i++) {
+    if (elements[i] === "Z") {
+      total -= parseInt(elements[i - 1]);
+    } else {
+      total += parseInt(elements[i]);
+    }
+  }
+
+  return total;
+}
diff --git "a/oh-chaeyeon/2\354\243\274\354\260\250_\354\212\244\355\203\235/Crane_Game.js" "b/oh-chaeyeon/2\354\243\274\354\260\250_\354\212\244\355\203\235/Crane_Game.js"
new file mode 100644
index 0000000..1c4f3f1
--- /dev/null
+++ "b/oh-chaeyeon/2\354\243\274\354\260\250_\354\212\244\355\203\235/Crane_Game.js"
@@ -0,0 +1,25 @@
+function solution(board, moves) {
+  const basket = [];
+  let count = 0;
+
+  for (let move of moves) {
+    const column = move - 1;
+
+    for (let i = 0; i < board.length; i++) {
+      if (board[i][column] !== 0) {
+        const doll = board[i][column];
+        board[i][column] = 0;
+
+        if (basket[basket.length - 1] === doll) {
+          basket.pop();
+          count += 2;
+        } else {
+          basket.push(doll);
+        }
+        break;
+      }
+    }
+  }
+
+  return count;
+}
diff --git "a/oh-chaeyeon/2\354\243\274\354\260\250_\354\212\244\355\203\235/Dart_Game.js" "b/oh-chaeyeon/2\354\243\274\354\260\250_\354\212\244\355\203\235/Dart_Game.js"
new file mode 100644
index 0000000..8b568f2
--- /dev/null
+++ "b/oh-chaeyeon/2\354\243\274\354\260\250_\354\212\244\355\203\235/Dart_Game.js"
@@ -0,0 +1,24 @@
+function solution(dartResult) {
+  const stack = [];
+  let i = 0;
+
+  while (i < dartResult.length) {
+    const isTen = dartResult[i] === "1" && dartResult[i + 1] === "0";
+    let score = isTen ? 10 : parseInt(dartResult[i]);
+    i += isTen ? 2 : 1;
+
+    const bonus = dartResult[i++];
+    score **= bonus === "S" ? 1 : bonus === "D" ? 2 : 3;
+
+    if (dartResult[i] === "*" || dartResult[i] === "#") {
+      score *= dartResult[i] === "*" ? 2 : -1;
+      if (dartResult[i++] === "*" && stack.length) {
+        stack[stack.length - 1] *= 2;
+      }
+    }
+
+    stack.push(score);
+  }
+
+  return stack.reduce((sum, cur) => sum + cur, 0);
+}
diff --git "a/oh-chaeyeon/2\354\243\274\354\260\250_\354\212\244\355\203\235/Delivery_Box.js" "b/oh-chaeyeon/2\354\243\274\354\260\250_\354\212\244\355\203\235/Delivery_Box.js"
new file mode 100644
index 0000000..3d13dd4
--- /dev/null
+++ "b/oh-chaeyeon/2\354\243\274\354\260\250_\354\212\244\355\203\235/Delivery_Box.js"
@@ -0,0 +1,18 @@
+function solution(order) {
+  let stack = [];
+  let current = 1;
+  let count = 0;
+
+  for (let box of order) {
+    while (current <= box) {
+      stack.push(current++);
+    }
+    if (stack.pop() === box) {
+      count++;
+    } else {
+      break;
+    }
+  }
+
+  return count;
+}
diff --git "a/oh-chaeyeon/2\354\243\274\354\260\250_\354\212\244\355\203\235/Hate_English.js" "b/oh-chaeyeon/2\354\243\274\354\260\250_\354\212\244\355\203\235/Hate_English.js"
new file mode 100644
index 0000000..245d676
--- /dev/null
+++ "b/oh-chaeyeon/2\354\243\274\354\260\250_\354\212\244\355\203\235/Hate_English.js"
@@ -0,0 +1,22 @@
+function solution(numbers) {
+  return parseInt(
+    numbers.replace(
+      /zero|one|two|three|four|five|six|seven|eight|nine/g,
+      (match) => {
+        const numWords = {
+          zero: "0",
+          one: "1",
+          two: "2",
+          three: "3",
+          four: "4",
+          five: "5",
+          six: "6",
+          seven: "7",
+          eight: "8",
+          nine: "9",
+        };
+        return numWords[match];
+      }
+    )
+  );
+}
diff --git "a/oh-chaeyeon/2\354\243\274\354\260\250_\354\212\244\355\203\235/Rotate_Parentheses.js" "b/oh-chaeyeon/2\354\243\274\354\260\250_\354\212\244\355\203\235/Rotate_Parentheses.js"
new file mode 100644
index 0000000..599ac03
--- /dev/null
+++ "b/oh-chaeyeon/2\354\243\274\354\260\250_\354\212\244\355\203\235/Rotate_Parentheses.js"
@@ -0,0 +1,25 @@
+function solution(s) {
+  let answer = 0;
+  for (let i = 0; i < s.length; i++) {
+    const rotated = s.slice(i) + s.slice(0, i);
+    if (isValid(rotated)) answer++;
+  }
+  return answer;
+}
+
+function isValid(str) {
+  const stack = [];
+  for (let c of str) {
+    if ("([{".includes(c)) stack.push(c);
+    else if (!stack.length || !isPair(stack.pop(), c)) return false;
+  }
+  return stack.length === 0;
+}
+
+function isPair(open, close) {
+  return (
+    (open === "(" && close === ")") ||
+    (open === "[" && close === "]") ||
+    (open === "{" && close === "}")
+  );
+}
diff --git "a/oh-chaeyeon/2\354\243\274\354\260\250_\354\212\244\355\203\235/Stock_Price.js" "b/oh-chaeyeon/2\354\243\274\354\260\250_\354\212\244\355\203\235/Stock_Price.js"
new file mode 100644
index 0000000..f5d8d0c
--- /dev/null
+++ "b/oh-chaeyeon/2\354\243\274\354\260\250_\354\212\244\355\203\235/Stock_Price.js"
@@ -0,0 +1,18 @@
+function solution(prices) {
+  const answer = Array(prices.length).fill(0);
+  const stack = [];
+
+  prices.forEach((price, i) => {
+    while (stack.length && prices[stack[stack.length - 1]] > price) {
+      const idx = stack.pop();
+      answer[idx] = i - idx;
+    }
+    stack.push(i);
+  });
+
+  stack.forEach((idx) => {
+    answer[idx] = prices.length - 1 - idx;
+  });
+
+  return answer;
+}
diff --git "a/oh-chaeyeon/2\354\243\274\354\260\250_\354\212\244\355\203\235/String_Calculation.js" "b/oh-chaeyeon/2\354\243\274\354\260\250_\354\212\244\355\203\235/String_Calculation.js"
new file mode 100644
index 0000000..50bd5cc
--- /dev/null
+++ "b/oh-chaeyeon/2\354\243\274\354\260\250_\354\212\244\355\203\235/String_Calculation.js"
@@ -0,0 +1,3 @@
+function solution(my_string) {
+  return eval(my_string);
+}
diff --git "a/oh-chaeyeon/2\354\243\274\354\260\250_\354\212\244\355\203\235/String_Reversal.js" "b/oh-chaeyeon/2\354\243\274\354\260\250_\354\212\244\355\203\235/String_Reversal.js"
new file mode 100644
index 0000000..cae1e0c
--- /dev/null
+++ "b/oh-chaeyeon/2\354\243\274\354\260\250_\354\212\244\355\203\235/String_Reversal.js"
@@ -0,0 +1,3 @@
+function solution(my_string) {
+  return my_string.split("").reverse().join("");
+}
diff --git "a/oh-chaeyeon/2\354\243\274\354\260\250_\354\212\244\355\203\235/Valid_Parentheses.js" "b/oh-chaeyeon/2\354\243\274\354\260\250_\354\212\244\355\203\235/Valid_Parentheses.js"
new file mode 100644
index 0000000..1aee364
--- /dev/null
+++ "b/oh-chaeyeon/2\354\243\274\354\260\250_\354\212\244\355\203\235/Valid_Parentheses.js"
@@ -0,0 +1,15 @@
+function solution(s) {
+  const stack = [];
+
+  for (let char of s) {
+    if (char === "(") {
+      stack.push(char);
+    } else if (stack.length > 0) {
+      stack.pop();
+    } else {
+      return false;
+    }
+  }
+
+  return stack.length === 0;
+}