It's so much easier to multiply fractions than add them when teaching kids they have to have a common denominator.
They really whine when they find out they're not done and they need to reduce!
Do your 4th graders know how lucky they are to have you as a teacher?
Tell them to learn it all as it comes up now & they won’t have to take remedial math classes in college where they will be expected to learn 9 months of math in one 14 - 16 week semester.