diff --git a/5_1.js b/5_1.js
new file mode 100644
index 0000000..1f0cddc
--- /dev/null
+++ b/5_1.js
@@ -0,0 +1,42 @@
+/* const startDateStr = '02 Aug 1985';
+const endDateStr = '03 Aug 1985'; */
+
+const startDateStr = '31 Jan 2022';
+const endDateStr = '03 Feb 2021';
+function dateDiff(startDateStr = '1 Jan 2022', endDateStr = '1 Jan 2023', unit = 'seconds') {
+  const startDate = new Date(startDateStr);
+  const endDate = new Date(endDateStr);
+  const result = Math.abs(endDate - startDate);
+  const unitDivisor = {
+    'seconds': result / 1000,
+    'minutes': result / 60000,
+    'hours': result / (1000 * 60 * 60),
+    'days': result / (1000 * 60 * 60 * 24)
+    
+
+
+  }
+  
+  // switch (unit) {
+  //   case 'seconds' :
+  //     result = result / 1000;
+  //     break;
+  //   case "minutes" :
+  //     result = result / 60000;
+  //     break;
+  //   case "hours" :
+  //     result = result / (1000 * 60 * 60);
+  //     break;
+  //    case "days" :
+  //     result = result / (1000 * 60 * 60 * 24);
+  //     break;
+  // }
+  console.log(unitDivisor[unit]);
+}
+
+dateDiff(endDateStr, startDateStr, 'days');
+
+console.log(result);
+
+
+
diff --git a/5_2.js b/5_2.js
new file mode 100644
index 0000000..391ad1e
--- /dev/null
+++ b/5_2.js
@@ -0,0 +1,18 @@
+function optimizer(data) {
+    const result = {};
+for (const [key, value] of Object.entries(data)) {
+    result[key.toLowerCase()] = parseFloat(value).toFixed(2);
+    
+}
+
+    return result;
+};
+
+const priceData = {
+    Apples: '23.4',
+    BANANAS: '48',
+    oRAngGEs: '48.7584',
+};
+
+let updatedPriceData = optimizer(priceData);
+console.log(updatedPriceData)    // {apples: '23.40', bananas: '48.00', oranges: '48.76'}
\ No newline at end of file
diff --git a/5_3.js b/5_3.js
new file mode 100644
index 0000000..a5e4f1e
--- /dev/null
+++ b/5_3.js
@@ -0,0 +1,24 @@
+function recursiveOddSumTo(number) {
+  if (number == 1)
+    return 1;
+  if (number % 2 == 1)
+    return (recursiveOddSumTo(number - 1) + number);
+  
+  return (recursiveOddSumTo(number - 1))
+};
+console.log(recursiveOddSumTo(1)) // 1
+console.log(recursiveOddSumTo(10)) // 25
+
+
+function iterativeOddSumTo(number) {
+  let sum = 0; 
+
+  for (i = 1; i <= number; i += 2) {
+    sum = sum + i;
+  }
+
+  return (sum);
+}
+
+console.log(iterativeOddSumTo(1)) // 1
+console.log(iterativeOddSumTo(10)) // 25
\ No newline at end of file