What the standard asks
Grade 4 number and operations includes adding and subtracting fractions that have equal denominators. The child should be able to show the work with objects or drawings that build toward a number line, not only by stacking two numerals.
A two-minute check at home
Put two strips of paper on the table, each marked in fourths. Ask them to join 1/4 and 2/4. They should land on 3/4, and they should be able to point to that same spot on a number line from 0 to 1. Then ask them to take 1/4 away from 3/4. If they can only recite a rule and cannot show the pieces, they are not done with this skill yet.
What it leads to next year
Fifth grade asks them to add and subtract fractions whose denominators are different. The equal-denominator work in 4.3(E) is the floor that work stands on.
This explainer does not claim that $100 for 100% lessons cover 4.3(E). It explains the Texas standard so you can check it yourself.