What is meant by “the condition”? I am imagining that in x + 3 = 7 that x is the unknown and 3 and 7 are the data? Is the condition equality and, if so, how do you use that information?
Some more complicated examples would probably help me understand.
It's more relevant in a word problem, where you need to extract the condition from text and translate it into syntactical math notation so you can compute.
"John wants to have 7 pizzas. He has already made 3 pizzas. How many more pizzas does he need to make?"
Data: 7 pizzas needed. 3 pizzas made.
Unknown: X pizzas more to make
Condition: X+3=7
Or for geometry diagram problems (diagram geometry is word problems where the words are pictures), where you have to extract the relationships from the diagram.
Some more complicated examples would probably help me understand.