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Finding the LCM, or Lowest Common Multiple, is the primary step for adding fractions that have unlike denominators. In the example: What is 1/4 + 2/5, we need to find the lowest common multiple of 4 and 5. One of the easiest tricks is to attempt to multiply the denominators. 4 x 5 = 20. In this example, 20 is in fact the lowest common multiple.
We need to make sure we not only change the denominators but the numerators as well. Remember in Algebra that whatever you do to one thing you must do to the other. So in our case:
- 1/4 * 5/5 = 5/20
- 2/5 * 4/4 = 8/20
- 5/20 + 8/20 = 13/20.
13 is a Prime number and therefore this fraction is simplified.
Wiki User
∙ 8y ago
Wiki User
∙ 8y agoTo convert unlike fractions to like fractions, it is necessary to find the LCM of the denominators, in this case called the least common denominator.
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When do you use LCM in math?
When you want to add or subtract unlike fractions.
When adding fractions with unlike denominators it is most helpful if the fractions are renamed using the?
If the denominators are not the same, then you have to use equivalent fractions which do have a common denominator . To do this, you need to find the least common multiple (LCM) of the two denominators. To add fractions with unlike denominators, rename the fractions with a common denominator.
Do you add and subtract like and unlike fractions in the same way?
no, to add and subtract like and unlike fractions the denominator has to be the same,
How do you add unlike fractions?
Change them to like fractions and proceed.
How do use LCM in the real world?
To add fractions.
What problems can be solved using gcf and LCM?
Finding the LCM will make adding and subtracting fractions easier.
How can the greatest common factor and least common multiple help you work with 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.
When you add or subtract fractions with unlike denominators why do you have to find LCM?
Because to add fractions, the denominators must be equal.
What is a situation where you would use LCM?
To add and subtract unlike fractions.
When do you use LCM in math?
When you want to add or subtract unlike fractions.
Why do you needto find the LCM?
Finding the LCM will help you when you need to add and subtract fractions.
Why should you find a LCM?
Finding an LCM will help when you want to add and subtract fractions.
How do GCF and LCM involve with the real world?
Use the GCF to reduce fractions. Use the LCM to add and subtract unlike fractions. Carpenters work with fractions a lot.
How can knowing the GCF and LCM help you when you add subtract and multiply 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.
How do you find the LCM multiple for two fractions?
The LCM is used for integers, not fractions. If you're trying to add unlike fractions, take the LCM of the denominators (known in this case as the least common denominator, or LCD), convert the fractions and proceed.
How is finding the LCM revelant when adding and subtracting fractions?
To add and subtract fractions, you need common denominators. To find the common denominator, find the LCM of the denominators you wish to add or subtract.
Why is it important to find the LCM of 2 numbers?
It will help when you want to add and subtract unlike fractions.
