In order to add or subtract fractions, the denominator (bottom number) has to be the same. In order to make it the same, you find the LCM and multiply the fraction by whatever is necessary to make the denominator the LCM. FOR EXAMPLE:
1/3 + 2/5
The LCM of 3 and 5 is 15.
To make the 3 in 1/3 15, you multiply the whole fraction by 5 over 5 (it simplifies to 1 so you aren't really changing the fraction by multiplying it by 1).
1/3 * 5/5 is 5/15
You multiply 2/5 times 3 over 3 using the same principle
2/5 * 3/3 is 6/15
NOW you can add 5/15 and 6/15 to get 11/15.
To add and subtract unlike fractions, find the LCM of the denominators and convert them to equivalent like fractions. You don't have to do anything to fractions to multiply them, but you may need to reduce one after multiplying. To do that, find the GCF of the numerator and the denominator and divide both of them by it. If the GCF is 1, the fraction is in its simplest form.
Knowing the LCM of the denominators will help you to find a least common denominator of unlike fractions, which will allow you to add and subtract them successfully. Knowing the GCF and LCM will not help you in multiplying them, but knowing the GCF of the numerator and denominator of a fraction will help you reduce it if necessary.
When adding and subtracting unlike fractions, it is necessary to find the LCM of the denominators, called the least common denominator. Once you have found the LCD, you can convert the fractions to equivalent fractions with a common denominator and proceed with the adding and/or subtracting. Finding an LCM will have no effect on multiplying fractions.
To add and subtract fractions, you need common denominators. To find the common denominator, take the LCM of the denominators you wish to add or subtract.
I assume you mean, with different denominators. If you want to add the fractions, subtract them, or compare them (determine which one is greater), you have to convert them to similar fractions (fractions with the same denominator) first. Converting to similar fractions is not necessary, and usually doesn't even help, if you want to multiply or divide fractions.
Finding the LCM will help you add and subtract fractions. Finding the GCF will help you reduce fractions.
Finding the GCF will help in simplifying fractions. Finding the LCM will help in adding and subtracting fractions.
Finding the GCF of the numerator and the denominator of a fraction and dividing them both by it will give you the simplest form of that fraction. Finding the LCM of unlike denominators and converting them to it will make it possible to add and subtract unlike fractions.
If you are adding fractions, finding the least common multiple makes the arithmetic easier. For instance if you add 3/4, 5/6 and 1/12 the LCM is 12. In the worst case, you might multiply 4x6x12 to get 288, and have to change each fraction to 288ths!
I assume you mean, with different denominators. If you want to add the fractions, subtract them, or compare them (determine which one is greater), you have to convert them to similar fractions (fractions with the same denominator) first. Converting to similar fractions is not necessary, and usually doesn't even help, if you want to multiply or divide fractions.
Finding the LCM will help you when you need to add and subtract fractions.
It will help when you are trying to add and subtract fractions.
Finding an LCM will help when you want to add and subtract fractions.
Finding the prime factorizations of the denominators will help you find the least common denominator. Converting to equivalent fractions with like denominators will allow you to subtract them successfully.
Knowing the least common multiple of the denominators will help you find a common denominator when adding and subtracting unlike fractions. Knowing the greatest common factor of the numerator and the denominator will help you reduce the fraction if possible.
Finding the LCM will help you add and subtract fractions. Finding the GCF will help you reduce fractions.
Knowing the LCM will help when adding or subtracting unlike fractions. By finding the LCM of the denominators, (called the lowest common denominator) you can convert unlike to like fractions and proceed with the adding or subtracting. Knowing the GCF helps reduce a fraction. By finding the GCF of the numerator and the denominator and dividing both of them by it, you can reduce a fraction to its lowest terms (simplest form). If the GCF is 1, the fraction is in its simplest form. You can successfully multiply fractions without knowing the GCF or LCM.
It will help when you want to add and subtract unlike fractions.
The LCM is used to help you add or subtract fractions with different denominators.
Quadratic equation
Knowing the LCM of the denominators of unlike fractions will help you find the least common denominator, a necessary step in adding and subtracting them. Knowing the GCF of a numerator and denominator will tell you if the fraction can be reduced.