Calculated default values in Power apps

Requirement: Adding the total value using calculated default values in fields

Create a blank canvas app, add label to the screen.

Now add 3 Text input controls. Add one more Text input ,for this add value of inputs as shown in below:

Default Property: Value(TextInput1.Text)+ Value(TextInput1_1.Text)+ Value(TextInput1_2.Text)

This will be calculated, when user enter the values in textinputs , the Result will automatically added to the Textinput1_4.