Why is 2 the only number that is always 4 when added multiplied or squared

There are infinite numbers that added or multiplied will give the same answer. But, if the require this two numbers to be the same, then we need to solve the following equation to see what we found out:

x + y = x * y

Given that we want the numbers to be equal, then y=x.

x + x = x * x

2x = x^2

x^2 - 2x = 0

x(x-2) = 0

We find that NOT only x=2 meets this requirement but also x=0.

Therefore, there is another number that when added, multiplied or squared gives the same result. The other number is zero!

We can prove it:

0 × 0 = 0

0 + 0 = 0