Understand addition and subtraction of fractions as joining and
separating parts referring to the same whole.
Math.4.NF.3c or 4.NF.B.3.C
Add and subtract mixed numbers with like denominators, e.g., by
replacing each mixed number with an equivalent fraction, and/or
by using properties of operations and the relationship between
addition and subtraction.
Math.4.NF.3d or 4.NF.B.3.D
Solve word problems involving addition and subtraction
of fractions referring to the same whole and having like
denominators, e.g., by using visual fraction models and equations
to represent the problem.