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Terminating Decimals – Definition, Theorem, Examples

Jo-ann Caballes

Updated on January 10, 2024

In the boundless universe of mathematics, we often encounter a diversity of numbers, each with unique properties and patterns. As we journey through this numerical cosmos, we come across a particular type of decimal number known as a terminating decimal. These decimals are like celestial bodies that mark the end of a constellation—they signify an end or “termination” to the sequence of digits after the decimal point. The Brighterly team is excited to guide you through this intriguing topic, demystifying its complexities and making it as understandable as counting from one to ten.

Terminating decimals are, essentially, rational numbers whose decimal representation concludes or “terminates” after a certain number of digits. For example, numbers such as 0.75, 0.4, and 3.14 are terminating decimals because their decimal representations do not go on indefinitely. Understanding these decimals will equip you with essential skills to decode the world of numbers and find a distinct rhythm in the beautiful dance of digits.

At Brighterly, we firmly believe that every mathematical concept, such as terminating decimals, is a building block that paves the way to a more comprehensive understanding of the mathematical universe. So, buckle up as we dive deeper into this exciting adventure!

What Is a Terminating Decimal?

In the captivating world of mathematics, we often encounter various types of numbers, one of which is known as the terminating decimal. A terminating decimal is a decimal number that has a finite number of digits. That is, it ends or “terminates” after a certain number of decimal places. For instance, the number 0.75 is a terminating decimal because it has two decimal places. Similarly, the number 3.14 also qualifies, as it has two decimal places. In essence, a terminating decimal doesn’t go on forever, unlike its counterpart, the non-terminating decimal.

A key point to remember is that terminating decimals are a subset of rational numbers. Rational numbers are numbers that can be expressed as the quotient or fraction of two integers, with the denominator not equal to zero. In the case of terminating decimals, these are rational numbers whose decimal representation stops or terminates after a specific number of digits. Math is Fun provides an excellent resource for understanding rational numbers.

How to Recognize a Terminating Decimal?

Recognizing a terminating decimal is relatively straightforward. It’s all about looking for the end – the termination. If a decimal number stops after a certain number of places, it’s a terminating decimal. On the contrary, if it goes on indefinitely without repeating, it’s a non-terminating decimal. And if it repeats a pattern indefinitely, it’s a recurring or repeating decimal.

However, when we deal with fractions, recognizing a terminating decimal might not be as obvious. Here’s a tip: a fraction will result in a terminating decimal if its denominator, when fully simplified, is a power of 10. Since 10 is the product of 2s and 5s, this rule extends to fractions where the denominator is a power of 2, a power of 5, or a product of both. You’ll find more details about this in the Decimal Fractions section on Maths Teacher.

Terminating Decimals Examples

Let’s look at some examples of terminating decimals. Numbers like 0.5, 0.125, 0.75, and 0.6 are all terminating decimals because they have a finite number of digits after the decimal point.

On the other hand, numbers like 1/3, which equals 0.333…, and 1/7, which equals 0.142857142857…, are not terminating decimals. The decimal representation of 1/3 goes on indefinitely with the digit 3, and 1/7 repeats the six-digit sequence 142857 infinitely, making these numbers non-terminating decimals.

How to Identify a Terminating Decimal

When identifying a terminating decimal, the key is to consider the denominator of the decimal when it is expressed as a fraction. If the denominator (after being fully simplified) is a power of 2 or 5 or a combination of both, then the decimal will terminate.

For example, the fraction 7/8 has a denominator of 8, which is a power of 2. When divided, this fraction gives a decimal of 0.875, which is a terminating decimal.

The fraction 3/5 has a denominator of 5, which is a power of 5. This fraction gives a decimal of 0.6, which is also a terminating decimal.

Theorems on Terminating Decimals

One key theorem on terminating decimals is this: A fraction in its simplest form (lowest terms) will yield a terminating decimal if and only if all the prime factors of the denominator are also prime factors of 10. As mentioned earlier, the prime factors of 10 are 2 and 5.

So, the denominator of a fraction can be composed only of these prime numbers (either one of them or both) if the decimal is to terminate. This theorem is foundational in understanding the nature of terminating decimals and is discussed in greater detail in the Converting Fractions to Decimals section on Math Goodies.

What Is a Non-Terminating Decimal?

A non-terminating decimal is the exact opposite of a terminating decimal. It is a decimal that does not end. Instead, it continues indefinitely. There are two types of non-terminating decimals: repeating and non-repeating. A repeating decimal is a decimal that has a pattern that repeats indefinitely, while a non-repeating decimal does not have a repeating pattern.

For example, 1/3 = 0.333…, which is a repeating decimal, and pi (approximately 3.14159…) is an example of a non-repeating decimal.

Facts Related to Terminating Decimals

Here are a few interesting facts related to terminating decimals:

1. Every terminating decimal can be expressed as a fraction.
2. All terminating decimals are rational numbers, but not all rational numbers are terminating decimals.
3. If a decimal is both non-repeating and non-terminating, it is an irrational number.

Solved Examples on Terminating Decimals

Let’s work on some solved examples on terminating decimals:

1. Is 5/8 a terminating decimal? Yes, because the denominator 8 is a power of 2. When simplified, 5/8 equals 0.625, which is a terminating decimal.
2. Is 7/9 a terminating decimal? No, because the denominator 9 is not a power of 2 or 5. When simplified, 7/9 equals 0.777…, which is a repeating decimal.

Practice Problems on Terminating Decimals

Now, let’s try some practice problems on terminating decimals:

1. Is 3/16 a terminating decimal?
2. Is 2/11 a terminating decimal?
3. What is 4/5 as a terminating decimal?

Conclusion

Decoding the mystery of terminating decimals is akin to embarking on an exciting adventure, unveiling the intricate patterns and harmonies in the realm of mathematics. The journey may seem daunting at first, but with Brighterly as your guide, every step brings you closer to a deeper understanding and appreciation of the mathematical universe.

Terminating decimals are an intrinsic part of our numerical system, playing a key role in calculations and mathematical reasoning. Understanding them not only enhances your math skills but also nurtures a broader perspective towards the interconnectedness of various mathematical concepts. With this knowledge, you’re not just learning numbers; you’re learning the language of the universe.

At Brighterly, we’re committed to illuminating your path in this journey, helping you make sense of complex concepts in an engaging and accessible way. With every article, we strive to turn the seemingly daunting world of mathematics into a fascinating and enjoyable exploration. Remember, every mathematical challenge is an opportunity to grow, and with terminating decimals under your belt, you’re one step closer to becoming a math whizz!

Frequently Asked Questions on Terminating Decimals

What is a terminating decimal?

A terminating decimal is a type of decimal number that concludes or “terminates” after a certain number of digits. Unlike non-terminating decimals that go on indefinitely, terminating decimals have a clear end point. For instance, the number 0.25 is a terminating decimal as it ends after two decimal places.

How do I know if a decimal is terminating?

Recognizing a terminating decimal involves examining the fractional equivalent of the decimal number. If the denominator of this fraction (when simplified to its lowest terms) is a power of 2, a power of 5, or a combination of both, the decimal representation of this fraction will be terminating. This rule arises from the fact that these are the prime factors of 10, which forms the base of our decimal system.

Are all rational numbers terminating decimals?

While all terminating decimals are indeed rational numbers, the converse isn’t always true. Rational numbers can be expressed as a fraction where both numerator and denominator are integers, and the denominator is not zero. However, not all fractions result in a terminating decimal. For instance, the fraction 1/3 is a rational number, but its decimal equivalent, 0.333…, does not terminate nor end, making it a non-terminating decimal.

Jo-ann Caballes

5 articles

As a seasoned educator with a Bachelor’s in Secondary Education and over three years of experience, I specialize in making mathematics accessible to students of all backgrounds through Brighterly. My expertise extends beyond teaching; I blog about innovative educational strategies and have a keen interest in child psychology and curriculum development. My approach is shaped by a belief in practical, real-life application of math, making learning both impactful and enjoyable.