diff --git a/package-lock.json b/package-lock.json
index 6ca9060..ad2ba9e 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1079,6 +1079,7 @@
       "version": "22.13.5",
       "resolved": "https://registry.npmjs.org/@types/node/-/node-22.13.5.tgz",
       "integrity": "sha512-+lTU0PxZXn0Dr1NBtC7Y8cR21AJr87dLLU953CWA6pMxxv/UDc7jYAY90upcrie1nRcD6XNG5HOYEDtgW5TxAg==",
+      "dev": true,
       "license": "MIT",
       "dependencies": {
         "undici-types": "~6.20.0"
@@ -4318,6 +4319,7 @@
       "version": "6.20.0",
       "resolved": "https://registry.npmjs.org/undici-types/-/undici-types-6.20.0.tgz",
       "integrity": "sha512-Ny6QZ2Nju20vw1SRHe3d9jVu6gJ+4e3+MMpqu7pqE5HT6WsTSlce++GQmK5UXS8mzV8DSYHrQH+Xrf2jVcuKNg==",
+      "dev": true,
       "license": "MIT"
     },
     "node_modules/update-browserslist-db": {
diff --git a/src/transactions.ts b/src/transactions.ts
index f1cd836..84bec41 100644
--- a/src/transactions.ts
+++ b/src/transactions.ts
@@ -22,7 +22,8 @@ const transactions: Transaction[] = [
 function filterIncomeTransactions(transactions: Transaction[]): Transaction[] {
   // write your code here...
 
-  return []; // replace empty array with what you see is fit
+  return transactions.filter(([type]) => type === "income");
+  // replace empty array with what you see is fit
 }
 
 // `filterExpenseTransactions` function that:
@@ -33,7 +34,7 @@ function filterIncomeTransactions(transactions: Transaction[]): Transaction[] {
 function filterExpenseTransactions(transactions: Transaction[]): Transaction[] {
   // write your code here...
 
-  return []; // replace empty array with what you see is fit
+  return transactions.filter(([type]) => type === "expense"); // replace empty array with what you see is fit
 }
 
 // `calculateTotalIncome` function that:
@@ -43,8 +44,9 @@ function filterExpenseTransactions(transactions: Transaction[]): Transaction[] {
 // calculateTotalIncome(transactions); // => 3200  (1000 + 1500 + 700)
 function calculateTotalIncome(transactions: Transaction[]): number {
   // write your code here...
-
-  return -1; // replace -1 with what you see is fit
+  return transactions
+    .filter(([type]) => type === "income")
+    .reduce((sum, [, amount]) => sum + amount, 0); // replace -1 with what you see is fit
 }
 
 // `calculateTotalExpenses` function that:
@@ -54,8 +56,9 @@ function calculateTotalIncome(transactions: Transaction[]): number {
 // calculateTotalExpenses(transactions); // => 800  (500 + 300)
 function calculateTotalExpenses(transactions: Transaction[]): number {
   // write your code here...
-
-  return -1; // replace -1 with what you see is fit
+  return transactions
+    .filter(([type]) => type === "expense")
+    .reduce((sum, [, amount]) => sum + amount, 0); // replace -1 with what you see is fit
 }
 
 // `calculateNetTotal` function that:
@@ -66,7 +69,9 @@ function calculateTotalExpenses(transactions: Transaction[]): number {
 function calculateNetTotal(transactions: Transaction[]): number {
   // write your code here...
 
-  return -1; // replace -1 with what you see is fit
+  return (
+    calculateTotalIncome(transactions) - calculateTotalExpenses(transactions)
+  ); // replace -1 with what you see is fit
 }
 
 // `filterSignificantTransactions` function that:
@@ -80,9 +85,7 @@ function filterSignificantTransactions(
   transactions: Transaction[],
   threshold: number
 ): Transaction[] {
-  // write your code here...
-
-  return []; // replace empty array with what you see is fit
+  return transactions.filter(([, amount]) => amount >= threshold); // replace empty array with what you see is fit
 }
 
 export {
@@ -93,4 +96,4 @@ export {
   calculateTotalExpenses,
   calculateNetTotal,
   filterSignificantTransactions,
-};
+};
\ No newline at end of file