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### Course: Early math review > Unit 4

Lesson 7: Repeated addition# Using arrays in word problems

Sal uses addition to solve array word problems. Created by Sal Khan.

## Want to join the conversation?

- Do you add the rows?(4 votes)
- You multiply the rows and columns, then you get your answer. You can also add the rows too which is recommended.(13 votes)

- Mommy were are u,daddy were are u?:((1 vote)

## Video transcript

- [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. And 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. It 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. And 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. So 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.