While DaGreenBoi has provided enough evidence to prove this statement is false, I can do it as well:

Imagine you have an object A, and an object B. The nature of the objects does not matter.

By your definition, putting object A and object B together will make an object C appear from nowhere, which is a direct violation of the laws of physics.

Another proof is by reverse engineering your solution to the equation. If 1+1 = 3, then 3÷2=1. However, by calculating this (in a similar manner as what DaGreenBoi did) you find that 3÷2 = 1.5, so this means that 1 = 1.5, which is false.