Answer:Asked:How many kilometers had he walked? Given:2.5 km, 4.25 kmOperation:AdditionNumber Sentence:2.5 km+4.25 km = NSolution:add 2.5 km and 4.25 kmAnswer:7 kmStep-by-step explanation:if you add 2.5 km and 4.5 km it will be 7 no matter if you change the position of numbers.