Is 21 a rational number?
Understand the Problem
The question asks whether the number 21 is a rational number. A rational number is defined as any number that can be expressed as the quotient or fraction of two integers, where the denominator is not zero. Since 21 can be written as 21/1, it qualifies as a rational number.
Answer
21 is a rational number.
Answer for screen readers
21 is a rational number.
Steps to Solve
- Identify the definition of rational numbers
A rational number is any number that can be expressed in the form $\frac{a}{b}$, where $a$ and $b$ are integers, and $b \neq 0$.
- Express 21 as a fraction
To determine if 21 is a rational number, we can express it as a fraction. We can write:
$$ 21 = \frac{21}{1} $$
Here, 21 is in the form of $\frac{a}{b}$ with $a = 21$ and $b = 1$.
- Check the denominator
Confirm that the denominator is not zero. In our fraction, $b = 1$, which is clearly not zero.
- Conclusion
Since 21 can be expressed as a fraction of two integers and the denominator is not zero, it is confirmed that 21 is a rational number.
21 is a rational number.
More Information
Rational numbers include all integers, fractions, and finite decimals. Since 21 can be represented as $\frac{21}{1}$, it fits into the category of rational numbers. This includes any whole number, as they can all be expressed with a denominator of 1.
Tips
- A common mistake is confusing whole numbers with irrational numbers. Remember, all integers (like 21) are rational because they can be expressed as fractions.
