Study guides

☆☆

Q: Why do you not use common denominators while multiplying fractions?

Write your answer...

Submit

Still have questions?

Continue Learning about Other Math

You can totally add fractions with unlike denominators. You have to first find the LCD (least common denominator) to make them the same denomintars. And then you can just simply add them. What you cannot do is add fractions with unlike denominators without changing them to fractions with like denominators. The reason being that you would be attempting to add fractions that are different sizes. 1/2 is not the same size as 1/3, so it would be like trying to add apples and oranges. You have to change them to a common size and that is the reason you have to find the least common denominator first. While you cannot add 1/2 and 1/3, you can add 3/6 and 2/6.

to add fractions the denominators must be the same. when you have unlike denominators find the LCM and rename the fractions Well first of all let's say you have one over seven and one over five ok so you multiply the denominators the bottom numbers ok so now both bottom numbers are 35 so now first let's work with 1/7 so now it's just the bottom number and now you ask yourself 7 times what equals 35 5 right so now you times five times 1 because that was your top number so now that fraction is 5/35 now let's work with the next one which is 1/5 so now u ask yourself 5 times what equals 35 7 right so you multiply 7 times 1 and get 7 so that fraction is now 7/35 so now you add 7/35 + 5/35 equals 12/35 hope that helped in order to add fractions with different denominators, you must first find a common denominator and convert both fractions to use that number as it's base. For example, 3/4 + 2/3 The common denominator is 12 because it is the lowest number that is divisible by both of them. To convert each fraction to use the common denominator (12) as its base, you multiply the numerator by the same as what you have to multiply the denominator by to get 12. In this case, for the first fraction (3/4), 4*3 = 12 so you multiply 3 (numerator) by 3 to get 9; which gives you 9/12 for the second fraction (2/3), 3*4 = 12 so you multiply 2 * 4 to get 8; which gives you 8/12 Now add the numerators while holding the denominator constant. This gives you the answer of 17/12 or 1 and 5/12

To compare two fractions, convert both fractions to a common denominator. In this case, the common denominator is 40. 7/8 is larger than 4/5. We can demonstrate this in several ways. In decimal 7/8 is 0.875 while 4/5 is 0.800. In fractions 7/8 is equivalent to 35/40 while 4/5 is 32/40. 7/8 is 1/8 less than 1, while 4/5 is 1/5 less than 1. We know that 1/8 is smaller than 1/5, so 1 minus 1/8 is more than 1 minus 1/5.

you do what makes sense given the numbers, if the fractions work out beautifully, you can just leave them as mixed numbers, otherwise it's best to keep them as improper fractions

1.02 - in terms of fractions, 1.006 is 1 and 6 thousandths, while 1.02 is 1 and 2 hundredths.

Related questions

You can totally add fractions with unlike denominators. You have to first find the LCD (least common denominator) to make them the same denomintars. And then you can just simply add them. What you cannot do is add fractions with unlike denominators without changing them to fractions with like denominators. The reason being that you would be attempting to add fractions that are different sizes. 1/2 is not the same size as 1/3, so it would be like trying to add apples and oranges. You have to change them to a common size and that is the reason you have to find the least common denominator first. While you cannot add 1/2 and 1/3, you can add 3/6 and 2/6.

Adding similar fractions is easy, but adding dissimilar ones requires an additional step. Before you begin, you must know a few important key terms. First, the number on the top of a fraction is called the numerator, while the number on the bottom of a fraction is called the denominator. Similar fractions have the same denominator, also called a common denominator. To add dissimilar fractions (fractions with different denominators), you must first convert the fractions so that the denominators are the same.

You convert them, using equivalent fractions, so that they have the same denominator - a common multiple of the deniminators. Then the denominator of the sum is the common multiple while the numerator is the sum of numerators of the converted fractions. Finally, you need to check if the answer can be simplified. Students are often instructed that they must use the least common multiple (LCM). This is not necessary: any common multiple will do, though the LCM will require smaller numbers and so may be easier.

Anyone who is trying to add or subtract fractions.

For example, 2/2 (two halves) is one whole, while 10/10 (ten tenths) is also one whole.

Adding and subtracting unlike fractions.

No, it does not.

You cannot add fractions with different denominators because they do not represent the same size parts of a whole. (A half is larger than a third, so you cannot add them together as equals until they are expressed with the same denominator.)When fractions have like denominators, we add the numerators and place them over the denominator, for example:2/7 + 3/7 = (2 + 3)/7 = 5/7We can add fractions with unlike denominators by finding their "least common denominator". For example: 2/3 + 5/6 can both be expressed in terms of a least common denominator (6). Multiply the numerator and denominator by the same number to convert the fraction.2/3 + 5/6 -- multiply the numerator and denominator of 2/3 by 2, and 2/3 = 4/64/6 + 5/6 = 9/6 or 11/2Another example : a common denominator for 3/4 and 1/5 would be 20and 3/4 = 15/20 [ (3 x 5)/(4 x 5) ]while 1/5 = 4/20 [ (1 x 4)/(5 x 4)So 3/4 plus 4/5 would become 15/20 + 4/20 = 19/20.

'Fractions' have nothing to do with the eye.

There are two main methods.The first is to use the least common multiple (LCM) of the two denominators to change both fractions to the same denominator. After that, it is simple:the bigger numerator belongs to the bigger fraction.The other method is to cross multiply and compare products.If you want to compare A/B and C/D, then compare AD and BC instead. The numerator of the bigger fraction is in the bigger multiple (shown in bold):If AD is bigger, then A/B is bigger while if BC is bigger then C/D is bigger.

It depends what subjects you are comparing it with. Addition and subtraction in fractions can be hard at first but it becomes easy in division and multiplication. I am learning fractions at the moment and it can become fun after a while if you loosen yourself. So yeah, fractions are really easy after a while as I said, and other maths can become easy after a while to.

first must find Least Common Denominator http://www.loisterms.com/lois21.htm First of all, if you want to know about adding fractions, check out "How to Add Fractions". Be sure to follow the math examples carefully. To subtract fractions, follow the same steps as for adding, except subtract where you would add. Now about those positive and negative signs. The rules are the same whether you are working with integers or fractions. I will give you a method of learning the rules for the signs that has worked for many other students. Copy off this "Rules for Integers" chart and paste it on a large index card. Put the card in your math book or folder and refer to it often while you are doing your homework. If you keep using the card, you will get better with the signs.

People also asked