Using arrays in word problems

0:00- [Instructor] We're told Lulu was packing for a trip. She put her clothes inside of her suitcase in two rows with five shirts in each row. So I guess what they're drawing here is this is her open suitcase, and each of these squares is a shirt. And you can see there's one, two, three, four, five shirts in the first row and then another five shirts in the second row.

0:24And then they ask us which expression, or I guess we could say expressions, could we use to find the total number of shirts Lulu packed? And so pause this video and think about which of these expressions could we use to find the total number of shirts. And I'll give you a hint.

0:38It could be more than one of these. All right, now let's work through this together. So before I even look at these choices, I can look up here and say, okay, I have five in that first row and then I have five in the second row. So I have two groups of five. So I could view this as five plus five total shirts.

0:58And you can see that's this choice right over here. Now, are there other ways to view this? Instead of viewing it as two groups of five, what if we viewed it as five groups of two? That's one group of two. That's another group of two, a third group of two, a fourth group of two, and a fifth group of two.

1:18So you could view it as these two plus these two plus these two plus these two plus these two, five groups of twos. Or you could say five twos, which we have right over here. We have five twos and we're adding them all together. So I like this choice as well.