Printable algebra and pre-algebra math worksheets for math grades ... - Free Printable

Thank you for uploading the worksheet. Since I can’t view or process images directly, I’ll solve the problem based on the text you provided — which appears to be a math worksheet titled “Using Letters as Numbers”.

This worksheet asks students to write algebraic expressions for each of the following word problems, using letters (variables) to represent unknown numbers.

Let’s go through each problem one by one and write the correct expression.

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Problem 1:

> Peter has 100 bills. His mother gives him x dollars more. How many dollars does he have altogether?

✔ Expression:
100 + x

*Explanation:* He starts with 100 dollars, and his mom gives him *x* more. So total = 100 + x.

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Problem 2:

> Maria has x boxes of 10 pencils. The teacher gives her another 20 pencils. How many pencils does she have altogether?

✔ Expression:
10x + 20

*Explanation:* Each box has 10 pencils, so x boxes = 10x pencils. Add 20 more → 10x + 20.

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Problem 3:

> John bought x hamburgers at $3 each and paid with a 20 dollar note. How much change did he get?

✔ Expression:
20 - 3x

*Explanation:* Cost of x hamburgers = 3 × x = 3x. He paid with $20, so change = 20 - 3x.

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Problem 4:

> I have 200 marbles and divide them among x girls. How many marbles will each girl get?

✔ Expression:
200 ÷ x or 200/x

*Explanation:* Total marbles (200) divided equally among x girls → 200/x.

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Problem 5:

> Peter is x years old. He is 4 times older than his sister. How old is his sister?

✔ Expression:
x ÷ 4 or x/4

*Explanation:* If Peter is 4 times older than his sister, then his sister’s age = Peter’s age ÷ 4 → x/4.

*(Note: Sometimes “4 times older” can be ambiguous in language, but in elementary math contexts, it usually means “4 times as old.”)*

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Problem 6:

> John earns x dollars per hour. Petra earns 2 dollars per hour less than John. How much does Petra earn per hour?

✔ Expression:
x - 2

*Explanation:* Petra earns $2 less than John → x - 2.

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Problem 7:

> I have x boxes of 5 paperclips. If I use 100 paperclips per hour, how many hours will I have left?

⚠️ Important Note: This question is poorly worded. It says “how many hours will I have left?” — but hours are time, not paperclips. It probably meant:

> “How many hours will the paperclips last?” or “How many hours can I use them?”

Assuming that’s what was intended:

✔ Expression:
(5x) ÷ 100 or 5x/100

*Explanation:* Total paperclips = 5 per box × x boxes = 5x. Used at 100 per hour → number of hours = 5x ÷ 100.

You could also simplify to x/20, since 5x/100 = x/20.

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Problem 8:

> Emily has x erasers and y pencils. How many erasers and pencils does she have in all?

✔ Expression:
x + y

*Explanation:* Total items = erasers + pencils = x + y.

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## ✔ Final Answers Summary:

1. 100 + x
2. 10x + 20
3. 20 - 3x
4. 200/x
5. x/4
6. x - 2
7. 5x/100 or x/20 *(assuming intended meaning)*
8. x + y

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## 📝 Teaching Tip:
This worksheet is designed to help students transition from arithmetic to algebra by replacing unknown quantities with variables (letters). Emphasize that:
- Variables stand for numbers we don’t know yet.
- Operations (+, –, ×, ÷) work the same way as with numbers.
- Always read the problem carefully — especially for tricky wording like “times older” or “left.”

Let me know if you’d like a printable version or practice problems like this!