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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.
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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.
