# Lucas had 2.3 pounds of grapes left over from his class party. The class ate 1.9 pounds of the grapes. How many pounds of grapes did Lucas buy?

Lucas had bought $4.2$ pounds of grapes.
The quantity of grapes ($x$) bought by Lucas is the sum of the grapes left over from the party and the grapes eaten at the party. Hence:
$x = 2.3 + 1.9$
$x = 4.2$