Printable primary math worksheet for math grades 1 to 6 based on ... - Free Printable

Problem: Using Letters as Numbers

The task is to write algebraic expressions for each of the given sentences. Let's solve each problem step by step.

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#### 1) John has 9 apples and \( x \) oranges. How many apples and oranges does John have altogether?

- Expression:
John has 9 apples and \( x \) oranges. To find the total number of fruits, we add the number of apples and oranges.
\[
\text{Total fruits} = 9 + x
\]

- Answer:
\[
\boxed{9 + x}
\]

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#### 2) Peter has \( y \) boxes of 8 candies. His mother gives him another 12 candies. How many candies does he have altogether?

- Expression:
Peter has \( y \) boxes, and each box contains 8 candies. So, the total number of candies from the boxes is \( 8y \). Additionally, his mother gives him 12 more candies. Therefore, the total number of candies is:
\[
\text{Total candies} = 8y + 12
\]

- Answer:
\[
\boxed{8y + 12}
\]

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#### 3) Mira bought \( n \) pencils at \$2 each. She gave the cashier \$20. How much change did she get?

- Expression:
Mira bought \( n \) pencils, and each pencil costs \$2. So, the total cost of the pencils is \( 2n \). She gave the cashier \$20, so the change she received is:
\[
\text{Change} = 20 - 2n
\]

- Answer:
\[
\boxed{20 - 2n}
\]

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#### 4) Father had 100 stickers and divided them among \( k \) boys. How many stickers did each boy get?

- Expression:
The father had 100 stickers, and he divided them equally among \( k \) boys. Therefore, each boy gets:
\[
\text{Stickers per boy} = \frac{100}{k}
\]

- Answer:
\[
\boxed{\frac{100}{k}}
\]

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#### 5) A girl is \( z \) years old. Her mother is 3 times older than her. How old is the girl’s mother?

- Expression:
The girl is \( z \) years old, and her mother is 3 times older. Therefore, the mother's age is:
\[
\text{Mother's age} = 3z
\]

- Answer:
\[
\boxed{3z}
\]

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#### 6) A boy is \( x \) years old. His father is 5 times older than him. How old are the boy and his father altogether?

- Expression:
The boy is \( x \) years old, and his father is 5 times older, so the father's age is \( 5x \). To find their total age, we add the boy's age and the father's age:
\[
\text{Total age} = x + 5x = 6x
\]

- Answer:
\[
\boxed{6x}
\]

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#### 7) Hane has 5 boxes of sweets. Each box contained \( y \) sweets. If she eats 12 sweets, how many sweets will she have left?

- Expression:
Hane has 5 boxes, and each box contains \( y \) sweets. So, the total number of sweets is \( 5y \). If she eats 12 sweets, the number of sweets left is:
\[
\text{Sweets left} = 5y - 12
\]

- Answer:
\[
\boxed{5y - 12}
\]

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#### 8) Mara has \( x \) apples and twice as many oranges. How many apples and bananas does Mara have?

- Expression:
Mara has \( x \) apples and twice as many oranges. However, the question asks about apples and bananas, but there is no mention of bananas in the problem. Assuming the question meant "oranges" instead of "bananas," we can proceed as follows:
- Number of oranges = \( 2x \)
- Total fruits (apples and oranges) = \( x + 2x = 3x \)

If the question indeed meant "bananas," then the answer would be different since no information about bananas is provided. For now, assuming it means "oranges":
\[
\text{Total fruits} = 3x
\]

- Answer:
\[
\boxed{3x}
\]

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Final Answers:

1. \(\boxed{9 + x}\)
2. \(\boxed{8y + 12}\)
3. \(\boxed{20 - 2n}\)
4. \(\boxed{\frac{100}{k}}\)
5. \(\boxed{3z}\)
6. \(\boxed{6x}\)
7. \(\boxed{5y - 12}\)
8. \(\boxed{3x}\) (assuming "bananas" was a typo and meant "oranges")

Final Boxed Answer:
\[
\boxed{9 + x, 8y + 12, 20 - 2n, \frac{100}{k}, 3z, 6x, 5y - 12, 3x}
\]