If it's not what You are looking for type in the equation solver your own equation and let us solve it.
0.45+x=4.30+0.35
We move all terms to the left:
0.45+x-(4.30+0.35)=0
We add all the numbers together, and all the variables
x+0.45-(4.65)=0
We add all the numbers together, and all the variables
x-4.2=0
We move all terms containing x to the left, all other terms to the right
x=4.2