What is the formula for converting a decimal to a fraction?

The correct understanding of converting a decimal to a fraction begins with the concept that a decimal represents a part of a whole, which can be expressed as a ratio of two integers, known as a fraction. The foundational relationship is that a decimal can be represented as a fraction with a numerator and a denominator.

When you take a decimal, you can express it in the form of a fraction by placing the decimal's digits over a power of ten. For example, the decimal 0.75 can be converted to the fraction 75/100, revealing the direct relationship where the decimal is equivalent to the numerator divided by the denominator.

This captures the essence of the first choice, where a decimal is defined as a ratio of the numerator to the denominator, which aligns with the standard representation of a fraction. Thus, understanding this relationship is key to directly converting decimals into fractions accurately.