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Why must denominators be the same when adding or subtracting fractions?
Wiki User
∙ 12y ago
You have to have like forms to add them or subtract one from the other if the answer is to be a single form quantity. You cannot subtract 2 Oranges from a dozen apples. You first would have to convert the apples to mush, then subtract the equivalent of 2 oranges worth of mush, and then see how much mush you have left. If you added 2 oranges to a dozen apples, you would first convert both to a common form, mush, then add the apple mush and the orange mush to see how much fruit mush you have. Similarly, with fractions, you have to convert them to a common form, referred to as their common denominator, then you can add or subtract to find the result in their common form. If you do not convert the fractions to a common form, or denominator, the resulting answer will look like the original question and not be an answer at all.
Wiki User
∙ 12y ago
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Why must you find a common denominator before adding fractions?
You can only add like to like. There is no mechanism for adding different types of fraction.
What is the rule for subtracting integers with the same signs?
if the signs are the same you must add its opposite.
What two fractions have a common denominator of 8?
One of the fractions must have the denominator 8. The other could have a denominator of 2, 4 or 8.
What is equal to 2 3 in fractions that the numerator will be 14?
14 = 2*7 so the denominator must be 3*7 = 21 Therefore the required fraction is 14/21
Can the sum of two mixed numbers be equel to 2 Explain why or why not?
No. Each mixed number is made of a whole number and a fraction. When you add them, you have the sum of two whole numbers and two fractions. Since each whole number must be at least ' 1 ', the sum of two whole numbers must be at least ' 2 ', and the two fractions will always make it more than ' 2 '.
How are adding fractions different?
When adding or subtracting fractions their denominators must be the same
What did you learn from adding and subtracting fractions?
I learned to always change the denominators before adding or subtracting the numerators. You must always have a common denominator before adding or subtracting.
When adding or subtracting fractions do you have to have the numerator the same or denominator?
The denominators must be the same, the numerators can be different.
how to rename fractions using LCM?
When adding or subtracting fractions with different denominators their lowest common denominator must be found first by using the LCM of their denominators
How does finding the least common multiple help you add fractions?
Because when adding or subtracting fractions the denominators must have the same values
What is the purpose of learning least common multiples?
When subtracting or adding fractions the denominators must be the same if they are not then the LCM must be found.
When do you use LCD in math?
When adding or subtracting fractions with different denominators then their LCD must be found in order to carry out the calculations.
Are the steps for like and unlike denominators the same or different?
It depends what you are doing with the fractions. If you are multiplying or dividing fraction, the denominators do not need to be the same and the calculation can be carried out immediately. If you are adding or subtracting fractions, the denominators must be the same; if you have different denominators, the fractions must first be changed into equivalent fractions with the same denominator. When the denominators are the same (or have been made the same as equivalent fractions from being different) the calculation can be carried out.
What you must have when you adding fractions?
Common denominators.
What information does the least common multiple of two numbers provide in a problem?
When adding or subtracting fractions with different denominators the lowest common denominator is needed and is found by finding the lowest common multiple of the denominators.
What are the step in subtracting disimilar fraction?
Same as for adding: If the denominators are not equal, you must first find a common denominator, then convert both fractions to that common denominator.
When adding or subtracting fractions you must get a?
A Common Denominator
