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## 3rd grade (Eureka Math/EngageNY)

### Unit 1: Lesson 2

Topic B: Division as an unknown factor problem# Visualizing division with arrays

CCSS.Math:

Sal uses arrays to represent division expressions.

## Want to join the conversation?

- 20÷4=5 you can do

5 rows and 4 columns and you can do 5+5x2=20.(15 votes)- Division is the opposite of multiple(1 vote)

- can you mutply with arrays?(4 votes)
- Yes, you can.
**number of rows**`x`

**number of columns**`=`

**Answer via arrays**(10 votes)

- what my question is is I'm wondering if it goes the same way, like addition or if its like subtraction, where it does'nt work vice versa.(8 votes)
- that's not how you spell don't(0 votes)

- do you know 200+1,0000000(6 votes)
- 100*9= 9 with two zeros after it, which is, 900.(3 votes)

- ohh thats very cool i have school work soon about this topic ! thank you so much this really helped me.(3 votes)
- Can you use multiplication method(3 votes)
- Oh yes you can use multiplication method as they are fact family . Ex : 80 divided by 10 is 8 and 8 divided by 10 is 80 .(1 vote)

- i have to grow into a baby dragon(2 votes)
- im a plant Ian Pulizzotto youre still a seed >:)(2 votes)

## Video transcript

- [Instructor] We have three
different pictures here, and my question to get us warmed up is which of these could
represent 20 divided by four? Pause this video and see
if you can figure that out. All right, so let's go
through each of these. And, actually, let's think about what each of them could represent. So how many total circles
do we have in this picture right over here? Let's see, we have one, two, three, four, and then we have four groups of four. So four, eight, 12, 16. So this looks like 16 circles. 16 circles divided into, we could do it as divided
into groups of four, or we could actually also view it as divided into four equal groups, because both of those are true. And we see that that is
going to be equal to four. So this one over here, it's really representing
16 divided by four, not 20 divided by four. Now, what about this one? Let's see, here, it looks
like we have one, two, three, four, five groups of one, two, three, four, five. So this looks like 25 circles divided into groups of five, or divided into five equals groups, which is, of course, equal to five. So this is 25 divided by
five, not 20 divided by four. Now, but what about this one? So let's see, we have one,
two, three, four, five, and we have, one, two,
three, four groups of five. So five, 10, 15, 20. So we definitely have 20 circles there. And we have divided it
into four equal groups. We have divided it into four equal groups, and so that's exactly
what we're talking about, or what we started talking about. This is 20 divided by four. And you can see, when you take 20 and divide it into four equal groups, then you get one, two, three,
four, five circles per group. And we're done.