add? dont you mean subtract?
Yeah banana
When you are adding or subtracting unlike fractions.
This is effectively the same as lining up the decimal points when adding or subtracting ordinary decimal fractions.
We look at the signs of numbers when we need to combine them. We subtract only if numbers have different signs, otherwise we add them. So that, if we have in an expression several positive and negative numbers, we prefer to group numbers with the same sign and add them in order to subtract just once. While with fractions we like to group fractions with the same denominator first, and after that we can combine all fractions by finding their LCD.
You need a common denominator for both.
yes you should use a common denominator when subtracting with fractions, it makes it much easier.
You need at least two numbers to find an LCM. And they need to be whole numbers, not fractions.
Yes
Yes.
Find a common denamonator.
When you are adding or subtracting fractions.
When you are adding or subtracting fractions.