Children in the elementary grades are expected to solve equations to demonstrate prealgebraic proficiency. Prealgebraic differences may emerge based equation type (i.e., standard vs. nonstandard), the operation shown or required for solution (i.e., addition or subtraction), and the position of the unknown. Prealgebraic differences may also be influenced based on arithmetic proficiency. We evaluated the performance of 1,796 1st- and 2nd-grade children on a measure of standard and nonstandard equations to learn whether arithmetic fluency predicts prealgebraic performance, which characteristics of prealgebraic items determine item difficulty, and whether certain demographic variables contribute to prealgebraic performance. Results indicate prealgebraic differences by grade level and season (i.e., fall or spring) of administration. Arithmetic influences prealgebraic performance, and nonstandard equations that require a relational understanding of the equal sign are most difficult for young children.