How do you do Addition and subtraction of dissimilar fractions?

Answer 1

you just undissimilarize them.

No just kidding. You need to find LCD, lowest common denominator. If you are too lazy, then just multiply the two denominators together. Basically, you take one denominator from fraction "A", and multiply that value to numerator and denominator of fraction "B". Do the same with Denominator "B" to fraction "A". Once you have the same denominator, you can add or subtract your numerators.

If you are doing a homework assignment and you are in 7th grade or below, you MUST reduce or else you will lose points. But if you're in anything beyond Algebra, nobody remotely cares about reducing fractions. Fraction reduction barely even matters in real life, since real practical science/engineering calculations are done in decimal points. In calculus, there's a TON of fraction work, but again none of that matters in real life because most calculus problems in real life are done numerically with decimals.