Getting this error

var dogAge = prompt("What is your dog's age?");
var humanAge = ((dogAge - 2) *4) + 21

alert("Your dog is " + humanAge " human years old");

var dogAge = prompt("What is your dog's age?");
var humanAge = ((dogAge - 2) *4) + 21

alert("Your dog is " + humanAge " human years old");

var dogAge = prompt("What is your dog's age?");
var humanAge = ((dogAge - 2) *4) + 21

alert("Your dog is " + humanAge " human years old");

var dogAge = prompt("What is your dog's age?");
var humanAge = ((dogAge - 2) *4) + 21

alert("Your dog is " + humanAge " human years old");

This is the code. I've tried this in vscode as well and prettier starts giving another error in my var humanAge and says it needs a

wtf.