a Understand two fractions as equivalent (equal) if they are the same size, or the same point on a number line.
b Recognize and generate simple equivalent fractions, e.g., $1/2 = 2/4$, $4/6 = 2/3$. Explain why the fractions are equivalent, e.g., by using a visual fraction model.
c Express whole numbers as fractions, and recognize fractions that are equivalent to whole numbers. Examples: Express $3$ in the form $3 = 3/1$; recognize that $6/1 = 6$; locate $4/4$ and $1$ at the same point of a number line diagram.
d Compare two fractions with the same numerator or the same denominator by reasoning about their size. Recognize that comparisons are valid only when the two fractions refer to the same whole. Record the results of comparisons with the symbols $>$, =, or $<$, and justify the conclusions, e.g., by using a visual fraction model.