Interpreting bar graphs: alligators
About this video
James graphed the number of alligators in three places. The video reads the bars (Chomp Lake 6, Reptile Creek 9, Bite Swamp 12), adds 6 + 9 = 15, then finds that Bite Swamp has 3 fewer alligators than the other two combined.
You'll be able to
- read values from a bar graph.
- solve a two-step "how many fewer" problem using a bar graph.
- add and subtract to compare amounts.
Key words
- bar graph
- A graph that uses bars to show and compare amounts.
- combined
- Put together, or added up.
- how many fewer
- How much smaller one amount is than another; found by subtracting.
Transcript
- [Voiceover] James counted the number of alligators in various local bodies of water and graphed the results. How many fewer alligators are in Bite Swamp than Chomp Lake and Reptile Creek combined? So, down here, we have this bar graph that James somehow survived to create after going to all these bodies of water and counting the alligators.
We'll hope he was behind a fence or something. So then, we're asked how many fewer alligators are in Bite Swamp than in Chomp Lake and Reptile Creek combined? So, we need to know first how many are in Chomp Lake and Reptile Creek combined before we can figure out how many fewer are in Bite Swamp.
So, let's look down here. Here's Chomp Lake sounding super scary, and it's bar lines up to six, so there's six alligators in Chomp Lake. Plus, in Reptile Creek, if we go over here to Reptile Creek this bar lines up to nine, so there's nine alligators hanging out in Reptile Creek.
Six plus nine, let's see nine plus one is 10, so we can make our six into a a five and a one, nine plus one is 10 plus five more equals 15. So, there's total of 15 alligators in Chomp Lake and Reptile Creek combined. Now, we can answer how many fewer than 15 are in Bite Swamp.
So, Bite Swamp down here, sounding the most dangerous of them all, has a bar that lines up to 12. So, 12, there's 12 alligators in Bite Swamp, so how many fewer is 12 than the amount in Chomp Lake and Reptile Creek combined, 15, so how much fewer is 12 than 15?
Well, if we have 15 and we take 12 away, that leaves us with three. Three fewer alligators in Bite Swamp than there are in Chomp Lake and Reptile Creek combined.
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