 So now let's think about this. When you say divide, we have to be very precise with what we're saying. What are we dividing? Why are we dividing? We're dividing one fourth of an hour because Carlos... Let's think of the simplest part of the question. So what do we want at our final? We want to know who returned home first, right? And what are they doing? They're running some errands, correct? Okay. Now if I want to know how much total time Carlos took, what do you think I should really be doing if I want to know total time instead of dividing? Multiplying. Multiplying? Why do you say that? Because I mean converting because you need to know... Think about it, okay? So we have one fourth of an hour, one half an hour, and one hour. If I want to know how much total time I took, should I be multiplying? No. What should I be doing? Adding. Ah, okay. Because then adding will give me the total time I took and what would I have to do with Mary as well? Adding. Can you add these fractions the way they are? Well, first of all, is one a fraction? No. No. What is it? A whole number. A whole number. How do I turn that one into a fraction? You need to... So how would I write any whole number as a fraction? You need to do it over one. Yes, put the whole number over one. So can you set up a numerical expression that shows the operation of addition for me? For Carlos? Let's actually write that. Let's write it. Let's start again. Okay, let's be precise. So start your work right here. Excellent. So this is your numerical expression. Can you add that the way it is? No. Why not? Because they don't have unlike denominators. They don't have common denominators. They don't have common denominators. So can you do me a favor? Can you find the common denominator? Find the common denominator and then add for me and I will come back to you. Okay?