diff --git a/data-and-functions-1/src/functions/getActiveUsers.js b/data-and-functions-1/src/functions/getActiveUsers.js
new file mode 100644
index 0000000..0897458
--- /dev/null
+++ b/data-and-functions-1/src/functions/getActiveUsers.js
@@ -0,0 +1,15 @@
+const getActiveUsers = (DATA, id) => {
+  if (DATA == null || DATA.users == null) {
+    return null
+  } else {
+    const activeUsers = []
+    DATA.users.forEach((user) => {
+      if (user.accountActive === true) {
+        activeUsers.push(user)
+      }
+    })
+    return activeUsers
+  }
+}
+
+export default getActiveUsers
diff --git a/data-and-functions-1/src/functions/getMostExpensiveProduct.js b/data-and-functions-1/src/functions/getMostExpensiveProduct.js
new file mode 100644
index 0000000..6a3ac05
--- /dev/null
+++ b/data-and-functions-1/src/functions/getMostExpensiveProduct.js
@@ -0,0 +1,24 @@
+
+const getMostExpensiveProduct = (DATA) => {
+  if (DATA == null || DATA.products == null) {
+    return null
+  } else {
+    let mostExpensive = DATA.products[0]
+    DATA.products.forEach((p) => {
+      if (mostExpensive === null || mostExpensive.price < p.price) {
+        mostExpensive = p
+      }
+    })
+    return mostExpensive
+  }
+}
+
+export default getMostExpensiveProduct
+
+// return data.products.reduce((mostExpensive, p) => {
+//   if (p.price > mostExpensive.price) {
+//     return p
+//   } else {
+//     return mostExpensive
+//   }
+// })
diff --git a/data-and-functions-1/src/functions/getOrderInfo.js b/data-and-functions-1/src/functions/getOrderInfo.js
new file mode 100644
index 0000000..71741a1
--- /dev/null
+++ b/data-and-functions-1/src/functions/getOrderInfo.js
@@ -0,0 +1,21 @@
+import getUserById from './getUserById'
+import getProductById from './getProductById'
+
+const getOrderInfo = (DATA) => {
+  if (DATA == null || DATA.orders == null) {
+    return null
+  } else {
+    const orderInfoArr = []
+    DATA.orders.forEach((o) => {
+      const orderInfo = {
+        orderId: o.id,
+        userName: getUserById(DATA, o.userId).name,
+        price: getProductById(DATA, o.productId).price
+      }
+      orderInfoArr.push(orderInfo)
+    })
+    return orderInfoArr
+  }
+}
+
+export default getOrderInfo
diff --git a/data-and-functions-1/src/functions/getProductById.js b/data-and-functions-1/src/functions/getProductById.js
new file mode 100644
index 0000000..a63ffe3
--- /dev/null
+++ b/data-and-functions-1/src/functions/getProductById.js
@@ -0,0 +1,14 @@
+const getProductById = (DATA, id) => {
+  if (DATA == null || DATA.users == null || id == null) {
+    return null
+  }
+  let product
+  DATA.products.forEach((p) => {
+    if (p.id === id) {
+      product = p
+    }
+  })
+  return product
+}
+
+export default getProductById
diff --git a/data-and-functions-1/src/functions/getUserById.js b/data-and-functions-1/src/functions/getUserById.js
new file mode 100644
index 0000000..a505dd4
--- /dev/null
+++ b/data-and-functions-1/src/functions/getUserById.js
@@ -0,0 +1,16 @@
+const getUserById = (DATA, id) => {
+  if (DATA == null || DATA.users == null || id == null) {
+    return null
+  }
+
+  let user
+
+  DATA.users.forEach((u) => {
+    if (u.id === id) {
+      user = u
+    }
+  })
+  return user
+}
+
+export default getUserById
diff --git a/data-and-functions-3/src/functions/addOrder.js b/data-and-functions-3/src/functions/addOrder.js
new file mode 100644
index 0000000..dedad6c
--- /dev/null
+++ b/data-and-functions-3/src/functions/addOrder.js
@@ -0,0 +1,15 @@
+
+const addOrder = (DATA, order) => {
+  if (!DATA || !DATA.orders || !order || typeof order !== 'object' || order.id === true) {
+    throw new Error('Error')
+  }
+  const getNewId = DATA.orders.id.length + 1
+
+  const newOrder = { id: getNewId, userId: 1, products: 1 }
+
+  DATA.orders.push(newOrder)
+
+  return newOrder
+}
+
+export default addOrder
diff --git a/data-and-functions-3/src/functions/addProduct.js b/data-and-functions-3/src/functions/addProduct.js
new file mode 100644
index 0000000..955c922
--- /dev/null
+++ b/data-and-functions-3/src/functions/addProduct.js
@@ -0,0 +1,12 @@
+
+const addProduct = (DATA, product) => {
+  if (!DATA || !DATA.products || !product || typeof product !== 'object' ) {
+    throw new Error('Error')
+  }
+
+  if (product.id === true) {
+    throw new Error('error')
+  }
+}
+
+export default addProduct