Something I learned at my consulting firm. If you are asked a question and the answer has three parts, A, B, and C, and you know A and B but you don't know C,

Something I learned at my consulting firm. If you are asked a question and the answer has three parts, A, B, and C, and you know A and B but you don't know C, lead with what you know, before asking about details of which you are unsure. "So how many HVAC systems are installed in Houston every year?" "Well, Houston has about 5 million people, which makes about 2 million households, so if half of household live in a house there are about 1 million homes in Houston.... Now, as to how many HVAC systems are installed every year, how long does the typical HVAC system last?" "About 25 years" "Okay then, that makes 1 million divided by 25, or 40,000 HVAC systems every year..."