Rational and Irrational Numbers Quiz worksheet with multiple-choice and fill-in-the-blank questions.
Two pages of a "Rational and Irrational Numbers Quiz" worksheet with exercises on converting decimals to fractions, identifying rational and irrational numbers, and writing fractions as decimals.
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Step-by-step solution for: Eighth Grade Rational and Irrational Numbers Quiz - Twinkl
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Step-by-step solution for: Eighth Grade Rational and Irrational Numbers Quiz - Twinkl
It looks like you've uploaded a "Rational and Irrational Numbers Quiz" with two pages of problems. I'll solve each problem step by step, explain the reasoning, and provide the correct answers.
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#### Problem 1: Write each decimal below as a fraction in simplest form.
a. -2.498
To convert a decimal to a fraction:
- Write it as a fraction over 1000 (since there are 3 decimal places):
$$
-2.498 = -\frac{2498}{1000}
$$
- Simplify the fraction:
- Divide numerator and denominator by 2:
$$
\frac{2498 ÷ 2}{1000 ÷ 2} = \frac{1249}{500}
$$
- So, $-\frac{1249}{500}$ is the simplified form.
✔ Answer: $-\frac{1249}{500}$
---
b. 0.12
- Write as: $\frac{12}{100}$
- Simplify: divide numerator and denominator by 4 → $\frac{3}{25}$
✔ Answer: $\frac{3}{25}$
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#### Problem 2: Write each fraction as a decimal.
a. $\frac{17}{2}$
- Divide: $17 ÷ 2 = 8.5$
✔ Answer: $8.5$
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b. $\frac{18}{100}$
- This is already a decimal: $0.18$
✔ Answer: $0.18$
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#### Problem 3: Determine if each number is rational or irrational. Place a checkmark in the corresponding box.
| Number | Irrational | Rational |
|--------------|------------|----------|
| $\frac{2\pi}{3}$ | ✔ | |
| $-0.77$ | | ✔ |
| $\sqrt{61}$ | ✔ | |
| $2.8$ | | ✔ |
| $\frac{\sqrt{90}}{25}$ | ✔ | |
Let’s go through each:
1. $\frac{2\pi}{3}$:
- $\pi$ is irrational → any non-zero multiple of $\pi$ is irrational → this is irrational.
2. $-0.77$:
- Terminating decimal → can be written as $-\frac{77}{100}$ → rational.
3. $\sqrt{61}$:
- 61 is not a perfect square → $\sqrt{61}$ is irrational.
4. $2.8$:
- Terminating decimal → $\frac{28}{10} = \frac{14}{5}$ → rational.
5. $\frac{\sqrt{90}}{25}$:
- $\sqrt{90} = \sqrt{9 \cdot 10} = 3\sqrt{10}$ → $\sqrt{10}$ is irrational → so entire expression is irrational.
✔ Final Table:
| Number | Irrational | Rational |
|------------------|------------|----------|
| $\frac{2\pi}{3}$ | ✔ | |
| $-0.77$ | | ✔ |
| $\sqrt{61}$ | ✔ | |
| $2.8$ | | ✔ |
| $\frac{\sqrt{90}}{25}$ | ✔ | |
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#### Problem 4: Circle all of the rational numbers.
List:
a. $4\pi$
b. $\frac{1}{3}$
c. $\sqrt{25}$
d. $-2.32875321...$
e. $\sqrt{2}$
f. $\sqrt{121}$
Now evaluate each:
- a. $4\pi$:
- $\pi$ is irrational → $4\pi$ is irrational
- b. $\frac{1}{3}$:
- Fraction → rational
- c. $\sqrt{25}$:
- $\sqrt{25} = 5$ → integer → rational
- d. $-2.32875321...$:
- The ellipsis (...) suggests a non-repeating, non-terminating decimal → likely irrational
- If it's truly non-repeating, it's irrational
- e. $\sqrt{2}$:
- Well-known irrational number → irrational
- f. $\sqrt{121}$:
- $\sqrt{121} = 11$ → integer → rational
✔ Rational numbers: b. $\frac{1}{3}$, c. $\sqrt{25}$, f. $\sqrt{121}$
So, circle: b, c, f
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This appears to be a duplicate or continuation of the same quiz.
Let me confirm that all problems on both pages are covered.
But wait — Page 2 has:
> Problem 3: Same as above (already solved)
> Problem 4: Same as above (already solved)
So both pages seem to have overlapping content. Likely, one is a copy or version.
---
---
#### Problem 1: Decimal to Fraction
- a. $-2.498 = -\frac{1249}{500}$
- b. $0.12 = \frac{3}{25}$
---
#### Problem 2: Fraction to Decimal
- a. $\frac{17}{2} = 8.5$
- b. $\frac{18}{100} = 0.18$
---
#### Problem 3: Rational vs Irrational
| Number | Irrational | Rational |
|--------------------|------------|----------|
| $\frac{2\pi}{3}$ | ✔ | |
| $-0.77$ | | ✔ |
| $\sqrt{61}$ | ✔ | |
| $2.8$ | | ✔ |
| $\frac{\sqrt{90}}{25}$ | ✔ | |
---
#### Problem 4: Circle Rational Numbers
- Rational: b. $\frac{1}{3}$, c. $\sqrt{25}$, f. $\sqrt{121}$
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- Rational Numbers: Can be written as a fraction $\frac{p}{q}$ where $p$ and $q$ are integers and $q \ne 0$. Includes terminating decimals, repeating decimals, and integers.
- Irrational Numbers: Cannot be expressed as a fraction. Non-repeating, non-terminating decimals. Examples: $\pi$, $\sqrt{2}$, $\sqrt{61}$, etc.
---
If you'd like, I can generate a clean printable version of the completed quiz! Let me know.
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🔹 Page 1: Rational and Irrational Numbers Quiz
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#### Problem 1: Write each decimal below as a fraction in simplest form.
a. -2.498
To convert a decimal to a fraction:
- Write it as a fraction over 1000 (since there are 3 decimal places):
$$
-2.498 = -\frac{2498}{1000}
$$
- Simplify the fraction:
- Divide numerator and denominator by 2:
$$
\frac{2498 ÷ 2}{1000 ÷ 2} = \frac{1249}{500}
$$
- So, $-\frac{1249}{500}$ is the simplified form.
✔ Answer: $-\frac{1249}{500}$
---
b. 0.12
- Write as: $\frac{12}{100}$
- Simplify: divide numerator and denominator by 4 → $\frac{3}{25}$
✔ Answer: $\frac{3}{25}$
---
#### Problem 2: Write each fraction as a decimal.
a. $\frac{17}{2}$
- Divide: $17 ÷ 2 = 8.5$
✔ Answer: $8.5$
---
b. $\frac{18}{100}$
- This is already a decimal: $0.18$
✔ Answer: $0.18$
---
#### Problem 3: Determine if each number is rational or irrational. Place a checkmark in the corresponding box.
| Number | Irrational | Rational |
|--------------|------------|----------|
| $\frac{2\pi}{3}$ | ✔ | |
| $-0.77$ | | ✔ |
| $\sqrt{61}$ | ✔ | |
| $2.8$ | | ✔ |
| $\frac{\sqrt{90}}{25}$ | ✔ | |
Let’s go through each:
1. $\frac{2\pi}{3}$:
- $\pi$ is irrational → any non-zero multiple of $\pi$ is irrational → this is irrational.
2. $-0.77$:
- Terminating decimal → can be written as $-\frac{77}{100}$ → rational.
3. $\sqrt{61}$:
- 61 is not a perfect square → $\sqrt{61}$ is irrational.
4. $2.8$:
- Terminating decimal → $\frac{28}{10} = \frac{14}{5}$ → rational.
5. $\frac{\sqrt{90}}{25}$:
- $\sqrt{90} = \sqrt{9 \cdot 10} = 3\sqrt{10}$ → $\sqrt{10}$ is irrational → so entire expression is irrational.
✔ Final Table:
| Number | Irrational | Rational |
|------------------|------------|----------|
| $\frac{2\pi}{3}$ | ✔ | |
| $-0.77$ | | ✔ |
| $\sqrt{61}$ | ✔ | |
| $2.8$ | | ✔ |
| $\frac{\sqrt{90}}{25}$ | ✔ | |
---
#### Problem 4: Circle all of the rational numbers.
List:
a. $4\pi$
b. $\frac{1}{3}$
c. $\sqrt{25}$
d. $-2.32875321...$
e. $\sqrt{2}$
f. $\sqrt{121}$
Now evaluate each:
- a. $4\pi$:
- $\pi$ is irrational → $4\pi$ is irrational
- b. $\frac{1}{3}$:
- Fraction → rational
- c. $\sqrt{25}$:
- $\sqrt{25} = 5$ → integer → rational
- d. $-2.32875321...$:
- The ellipsis (...) suggests a non-repeating, non-terminating decimal → likely irrational
- If it's truly non-repeating, it's irrational
- e. $\sqrt{2}$:
- Well-known irrational number → irrational
- f. $\sqrt{121}$:
- $\sqrt{121} = 11$ → integer → rational
✔ Rational numbers: b. $\frac{1}{3}$, c. $\sqrt{25}$, f. $\sqrt{121}$
So, circle: b, c, f
---
🔹 Page 2: Additional Problems
This appears to be a duplicate or continuation of the same quiz.
Let me confirm that all problems on both pages are covered.
But wait — Page 2 has:
> Problem 3: Same as above (already solved)
> Problem 4: Same as above (already solved)
So both pages seem to have overlapping content. Likely, one is a copy or version.
---
✔ Final Answers Summary
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#### Problem 1: Decimal to Fraction
- a. $-2.498 = -\frac{1249}{500}$
- b. $0.12 = \frac{3}{25}$
---
#### Problem 2: Fraction to Decimal
- a. $\frac{17}{2} = 8.5$
- b. $\frac{18}{100} = 0.18$
---
#### Problem 3: Rational vs Irrational
| Number | Irrational | Rational |
|--------------------|------------|----------|
| $\frac{2\pi}{3}$ | ✔ | |
| $-0.77$ | | ✔ |
| $\sqrt{61}$ | ✔ | |
| $2.8$ | | ✔ |
| $\frac{\sqrt{90}}{25}$ | ✔ | |
---
#### Problem 4: Circle Rational Numbers
- Rational: b. $\frac{1}{3}$, c. $\sqrt{25}$, f. $\sqrt{121}$
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📌 Key Concepts Explained:
- Rational Numbers: Can be written as a fraction $\frac{p}{q}$ where $p$ and $q$ are integers and $q \ne 0$. Includes terminating decimals, repeating decimals, and integers.
- Irrational Numbers: Cannot be expressed as a fraction. Non-repeating, non-terminating decimals. Examples: $\pi$, $\sqrt{2}$, $\sqrt{61}$, etc.
---
If you'd like, I can generate a clean printable version of the completed quiz! Let me know.
Parent Tip: Review the logic above to help your child master the concept of rational numbers worksheet 8th grade.