WEBVTT

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This lesson is called variables in envelopes.

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We're going to learn how we can build sentences when we're still missing pieces of information.

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Most of us are already familiar with the idea of filling in a blank.

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We do it when we're
putting our name on our homework.

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Sometimes, there's more than one blank that needs to be filled out, and in that case,

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we give the blank a label so that we know which piece
of information goes where.

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Variables are placeholders for pieces of information that can change.

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By using a variable for the missing information, we can continue working on whatever we were doing,

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and let someone else fill in information later.

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In software, we use variables a lot.

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We use variables as placeholders for name, email address, and even username.

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That way, we can let the program know where those details will appear

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after the user fills them in.

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We use variables all the time in our work.

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Any time you need to store a piece of information
for later, we use a variable. Let's say we

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Let's say we need to count the number of times the user has tweeted.

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Every time that user tweets, we'll add one to that number.

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And every time
the user deletes a tweet, we'll decrease that number by one.

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Anytime we need to know how
many times that user has tweeted,

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we'll just look at that variable.