It is occur due to Numbers of signal input in the multiplication/division block
After Mux block there are three sinal are caring, moreover you have used multiplication block of single signals
Go inside the Multiplication block and replace (*) with (***) if you have three input signals
To your help, I have also attached an image of the inside of your model.
You need to change in all sub system of your model as per requirements
I hope it will be helpful for you
Pemendra Kumar Pardhi