Fraction Conversion

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Mentor: Look at the number "0.75". What does that remind you of?

Student: It looks like seventy-five cents.

Mentor: Exactly. When a number like 0.75 is written without the dollar sign, it doesn't show money anymore. We call that a decimal. Have you ever heard that word before?

Student: I've heard it when we talk about fractions, but I don't see what that number has to do with fractions.

Mentor: Good point. Let's think about money for a moment. How many cents are in a dollar?

Student: One hundred cents are in a dollar.

Mentor: That's right. How do you write one dollar?

Student: $1.00

Mentor: That's right. The 1 represents the number of dollars, but why do we write the two zeroes?

Student: They show how many cents there are.

Mentor: Exactly. Try to tell me two things that the word quarter makes you think of.

Student: Money and fractions.

Mentor: Exactly. We write one quarter of a dollar as "$0.25". That's in money form, but it's almost the same in fractions and decimals. 1/4 of 1 whole is 0.25 in decimal form.

Student: Where did the 25 come from? I understand in money because a quarter is 25 cents, but 25 has nothing to do with 1/4.

Mentor: That's a really good point, but the 25 actually does have something to do with 1/4.

Student: How? None of those numbers are the same.

Mentor: Why do you think we call the coins that are worth 25 cents "quarters"?

Student: Because 25 cents is one-quarter of a dollar.

Mentor: How do you write one quarter as a fraction?

Student: Oh, I get it. It's 1/4. 25 cents is 1/4 of a dollar. A dollar is 100 cents, so 25 is 1/4 of 100.

Mentor: Right. Decimals just take a fraction use place value to express it. Since there are two places, this decimal is like saying, "what is this fraction of one hundred?" So the decimal form of 1/4 is 0.25. What would be the decimal form of 1/100?

Student: That's easy! 0.01

Mentor: You're exactly right. Now I think you're ready to convert more difficult fractions into decimals.

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