Is 0.398 a whole number, interger, rational number, irrational number, or a real number

0.398 is a rational real number.

To solve this question, we need to understand the sets of numbers.

0.398 has a finite number of decimal digits, so it is a rational real number, as all rationals are real too.

A similar question is found at link

We can define a rational number as any number that can be written as the quotient of two integer numbers.

We will see that our number is a rational number.

Here we have the number 0.398, and we can try to rewrite it as the quotient of two whole numbers.

We can see that we have 3 digits after the decimal point, so we need to multiply and divide our number by 10^3

We will get:

We just saw that we can write our number as the quotient of two whole numbers, then we can conclude that our number is a rational number.

If you want to learn more, you can read:

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step-by-step explanation: