I need a reveiw on how to use the LCD least common denominator

to add and subtract

Is 6/28 the lowest common denominator or 3/7

To add or subtract fractions, you need to find a common denominator. The least common denominator (LCD) is the smallest number that all the denominators in the fractions can evenly divide into. Here's a step-by-step explanation on how to use the LCD to add and subtract fractions:

1. Identify the denominators of the fractions you want to add or subtract.

2. Find the least common multiple (LCM) of the denominators. The LCM is the smallest multiple that all the denominators have in common. To find the LCM, you can use various methods, such as prime factorization or the multiplication method. For simplicity, let's use the multiplication method.

3. Begin by writing down the prime factorization of each denominator. For example, if you have fractions with denominators 4 and 6, the prime factorization of 4 is 2^2 and of 6 is 2 * 3.

4. Identify the highest power of each prime number between all the denominators. In our example, the highest power of 2 is 2^2 and the highest power of 3 is 3.

5. Multiply all the highest powers of prime numbers together to get the LCM. In our example, the LCM would be 2^2 * 3 = 12.

6. Now that you have the LCD, you need to adjust the numerators of the fractions to reflect the new denominator. To do this, multiply both the numerator and denominator of each fraction by the same number that transforms the original denominator into the LCD. For example, if you have a fraction with a denominator of 4 and want to convert it to a denominator of 12, you would multiply the numerator and denominator by 3.

7. Once all the fractions have the same denominator, you can add or subtract the numerators. Keep the denominator the same. For example, if you have fractions 3/4 and 2/6, convert them both to have a denominator of 12. The fractions become 9/12 and 4/12. Now you can add or subtract the numerators: 9/12 + 4/12 = 13/12.

8. Simplify the resulting fraction if possible. In our example, the fraction 13/12 is an improper fraction. You can simplify it to 1 and 1/12.

Remember to always simplify your fractions whenever possible to have the most neat and accurate answer.

By following these steps, you can add or subtract fractions using the least common denominator (LCD).