Done nullability task

build.gradle.kts

@@ -1,5 +1,5 @@
 plugins {
-    kotlin("jvm") version "1.8.0"
+    id("org.jetbrains.kotlin.jvm") version "1.8.0"
     application
     id("io.gitlab.arturbosch.detekt") version "1.23.3"
 }
@@ -20,7 +20,7 @@ tasks.test {
 }
 
 kotlin {
-    jvmToolchain(11)
+    jvmToolchain(17)
 }
 
 detekt {

settings.gradle.kts

@@ -1,3 +1,8 @@
-
 rootProject.name = "kt-nullability"
 
+pluginManagement {
+    repositories {
+        gradlePluginPortal()
+        mavenCentral()
+    }
+}

src/main/kotlin/mate/academy/NumberTransformation.kt

@@ -6,6 +6,11 @@ package mate.academy
     If the number is not present return null
  */
 
-fun getReminder(numberStr: String?) : Int? {
-    return null
+const val TIMES = 3
+const val PLUS = 10
+const val REM = 11
+
+fun getReminder(numberStr: String?): Int? {
+    val number = numberStr?.toInt() ?: return null
+    return number.times(TIMES).plus(PLUS).rem(REM)
 }

src/main/kotlin/mate/academy/TotalPrice.kt

@@ -4,6 +4,11 @@ package mate.academy
     Calculate the products total price based on the provide price per product and products amount.
     If the price is not provided, use default price per product equal to 29.99
  */
-fun calculateTotalPrice(pricePerProduct: Double?, count: Int) : Double {
-    return 0.0
+
+const val PRICE = 29.99
+
+fun calculateTotalPrice(pricePerProduct: Double?, count: Int): Double {
+
+    val price = pricePerProduct ?: PRICE;
+    return price * count
 }