Algebra Readiness Test is given to eligible students in elementary school or middle school to test their ability to take more challenging mathematics coursework. Algebra Readiness Test (a.k.a Iowa Algebra Readiness Assessment,IARA in Iowa) is given to students who have scored high in NWEA/MAP testing, and in state administered standardized tests like Iowa Assessments. IARA can be given to students as early as 4th grade or 5th grade (depending on the school district) to eligible students to place the them in secondary mathematics curriculum. What this means is that a 4th grader who takes it and passes can start studying pre-algebra in 5th grade and skip 5th grade and 6th grade mathematics. For kids who have an aptitude in maths and are into STEM careers, taking higher level math classes in middle school through high school will help them stand out in college applications and also prep them for college. They can also take college level math classes in high school and save time and money.
Some of the concepts tested are integer operations, simplifying algebraic expression with one variables, order of operations, interpreting line/bar graphs etc. Here are links to a few worksheets to help prep for the test.
You can find more information about IARA here.