About this video
A word problem asks how many liters of soda there are for a party. Sal picks out the useful facts (5 bottles, 2 liters each), ignores the rest, and works out 5 × 2 = 10 liters.
You'll be able to
- decide which facts in a word problem I need.
- use multiplication to find a total of equal groups.
- solve a word problem like 5 bottles of 2 liters each.
Key words
- liter
- A unit for measuring how much liquid there is.
- irrelevant information
- Facts in a problem that you don't need to answer the question.
- multiplication
- Adding equal groups quickly, like 5 groups of 2 is 5 × 2.
Transcript
So we're asked, "how many liters of soda do we have for the party?" And they give us all of this other information. I encourage you to pause this video and think about which of this information you actually need to answer this first question and then try to answer the question: "How many liters of soda do we have for the party?" So pause now.
Let's look at this information: "20 people are coming to the party." This doesn't let us know how many liters we actually have. So we know we can ignore this. "We have purchased 5 bottles of soda for the party." Well, this seems useful - we're going to have 5 bottles of soda.
So that's 1... 2... 3.... 4.... and 5 bottles of soda. That's this piece of information right over here. If only we now knew how much soda is in each bottle. "The party will last for 3 hours." This has nothing to do with how many liters of soda we have. "Each bottle has 2 liters of soda." This is interesting.
This is 2 liters... this is 2 liters... this is 2 liters... this is 2 liters... and that is 2 liters. If we wanted to figure out the total number of liters of soda we have, We have 5 bottles, and each of them are 2 liters each. So we have 5 times 2 And what is that equal to?
5 times 2 is the same thing as 2 plus 2 plus 2 plus 2 plus 2 You have five 2's added together. Let me write this down... Which is equal to: 2, 4, 6, 8, 10. 5 times 2 is 10. We have 10 liters of soda for the party. We're able to answer it without even looking at this last one. This last one tells us how many bottles of soda we had for the picnic last week.
which doesn't seem related at all to our current party.
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