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.
If the fractions have the same denominator, add and subtract the numerators as if the denominators weren't there and put the result over that denominator. Reduce if possible. If the fractions have different denominators, find the LCM of the denominators and convert the fractions to equivalent fractions with like denominators. Then add and subtract the numerators as if the denominators weren't there and put the result over that denominator. Reduce if possible.
No, the denominators have to be the same.
In fractions, you can NEVER add or subtract
convert at least one of them so that they have the same denominator, then proceed with the addition or subtraction
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.
If the fractions have the same denominator, add and subtract the numerators as if the denominators weren't there and put the result over that denominator. Reduce if possible. If the fractions have different denominators, find the LCM of the denominators and convert the fractions to equivalent fractions with like denominators. Then add and subtract the numerators as if the denominators weren't there and put the result over that denominator. Reduce if possible.
The same way you would add or subtract whole numbers, leaving the denominators alone.
No, the denominators have to be the same.
In fractions, you can NEVER add or subtract
Because to add fractions, the denominators must be equal.
The denominators must be the same before you can add or subtract fractions.
It stays the same. Only the numerators change.
We can only add or subtract fractions if they have the same denominators
In order to subtract or add fractions the denominators must be the same and that's why the LCD must be found.
Whether the denominators are common or not.
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.