Arithmetic (all content)
Sal solves word problems comparing 2 numbers. Numbers in the problems are less than 10.
- [Voiceover] So they tell us that Alexander has nine marbles, Emily has five marbles. And then we're asked, how many more marbles does Alexander have than Emily? So pause the video and try to see if you could figure this out. Now let's work this out together. So let's just draw it out. Alexander has nine marbles. So we could draw his marbles. So one, two, three four, five six, seven eight, nine. And Emily has five marbles. One, two, three, four, five. So how many more marbles does Alexander have than Emily? Well we can see it in this picture right over here. These are all the... So, up until this point this is the same number that Alexander has as Emily. And then Alexander has... Alexander has... We see it right over here, he has one, two, three, four more marbles. Now what's another way that we could have thought about it? Well, Alexander has nine marbles and if you were to subtract the number of marbles Emily has, that's how much more marbles Alexander has. That's how much more nine is than five. So you could have said nine minus five is equal to... Is equal to the four... the four marbles. That's how much more marbles Alexander has than Emily. Let's do another one of these. Noa was mailing two letters. The heavier letter... The heavier letter had eight stamps. The lighter letter had five fewer stamps. How many stamps did the lighter letter have? So once again, try to pause this video and see if you can figure it out on your own. So the heavier letter, it's always useful to just, well, what are they telling us? So they are saying, just write down whatever information they give us. So the heavier letter has eight stamps, the lighter letter has five fewer stamps. So do we know how many the lighter letter has? Well not immediately. That's what they're actually asking us. How many stamps did the lighter letter have? But it's five fewer. Five fewer than what? Five fewer than eight stamps. And so we could write that. If we have eight stamps and we want to go five fewer than that... Five fewer... Well that's going to be eight minus five. This is five fewer than eight, which is going to be equal to three. The lighter letter has three stamps. Now another way you could have thought about it, The heavier letter had eight stamps. Let's draw eight stamps. So one, two, three, four, five, six, seven, and eight. That's how much the heavier letter had. The lighter letter had five fewer stamps. Let's take away one, two, three four, five. And what are you going to be left with? Well you're going to be left with these three stamps right over here. This is how many stamps the lighter letter had.