Make them into equivalent fractions with the same denominator, then the numerators can be subtracted and the resultant fraction simplified (if possible).
The first choice is the denominator for the equivalent fractions. Ideally this should be the lowest common multiple (LCM) of the given denominators, but just multiplying the two given denominators together will do.
The fractions can then be made into equivalent fractions with this chosen denominator.
If finding the LCM is too difficult, a simple "butterfly" (or "cross multiply") method can be used:
eg 3/5 - 1/2 = 3x2/5x2 - 5x1/5x2
= 6/10 - 5/10
= 1/10
eg 5/6 - 1/2 = 5x2/6x2 - 6x1/6x2
= 10/12 - 6/12
= 4/12
= 1x4/3x4
= 1/3
The same method is used for addition of fractions with different denominators: add instead of subtract the numerators of the equivalent fractions.
Because you can't add or subtract fractions that have different denominators. Making them like fractions, by multiplying so the denominators are the same, you can add and/or subtract them.
In fractions, you can NEVER add or subtract
unlike denominators: the bottom number of a fraction. to have unlike denominators you must have two fractions with a different number on the bottom of each fraction.
Subtract as if there were no denominators.
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.
It will enable you to add and subtract fractions with unlike denominators.
Because you can't add or subtract fractions that have different denominators. Making them like fractions, by multiplying so the denominators are the same, you can add and/or subtract them.
In fractions, you can NEVER add or subtract
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.
Multiplying the denominators together of two or more unlike fractions will get you a common multiple.
unlike denominators: the bottom number of a fraction. to have unlike denominators you must have two fractions with a different number on the bottom of each fraction.
Subtract as if there were no denominators.
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.
multiply the two denominators
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. Then add and simplify.
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. Then add and simplify.
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.