Why do fractions need to have a common denominator before you add or subtract them

It's easy to add and subtract like fractions, or fractions with the same denominator. You just add/subtract the numerators and keep the same denominator. The hard part is when you add or subtract fractions that have different denominators. To do this, you should know how to find the least common denominator

So it will be easier to solve the answer that way rather than a huge number

Sao rồi means why, i hope it

The 5th amendment allowed this to happen.