Like @thecil said, When you console.log these variables, console.log() takes it as a string. So basically it just combines the letters together. It does not “add” them.
So, If you want to see all your answers together you would do something like this.
var Milk = 2;
var Eggs = 1.5;
var Cheese = 4;
var Yoghurt = 1.2;
var Total = Milk + Eggs + Cheese + Yoghurt //the actual addition happens with numbers
//here below it takes that number and shows it as a string
console.log("The total bill for your grocery shopping will be " + "€ " + Total);
This way you will be able to see the answer.
If you want to go fancy and do the calculations in the console log statement itself, you need to explicitly mention that these are numbers and they should be added first then displayed as strings. It can be done by putting brackets –
//whatever in the bracket is treated as numbers and added up, then it is displayed as string (basically text)
console.log("The total bill for your grocery shopping will be " + "€ " + (Milk + Eggs + Cheese + Yoghurt) );
Hope this clears it out.