remedial
adj.adj. intended to help someone improve a basic skill they find difficult, or to fix a problem. You often hear this about extra classes for students who are falling behind.
adj. intended as a remedy or cure; specifically, relating to teaching or learning for students who require additional support to reach standard levels. Often used attributively before a noun.
He takes a remedial math class on Tuesday nights.
The school introduced a remedial reading program to help students who had fallen behind during the long summer break.
While the immediate focus was on remedial measures to stabilize the economy, the long-term strategy required a complete overhaul of the nation's aging infrastructure and tax code.
From Latin remediālis. By surface analysis, remedy + -al.
Typically precedes the noun it modifies; often pairs with 'education', 'action', or 'measures'.