At the Elsass home in Dublin, Monday night is math night.

That's when tutor Manar Adrabbo comes by to work with third-grader Evan Elsass, the youngest of the family's three sons.

The focus of one recent session: symmetry.

"If you fold it that way, it would be the same," Evan said, underscoring his grasp of the concept by drawing a line across a figure in his workbook.

It's the kind of eureka moment that tutors -- and the parents who hire them -- welcome. And with the school year coming to a close, it's the kind of moment that more parents are

Those with children in elementary school want to make sure their little ones master the basics. Middle-schoolers' parents worry about classroom placements and
standardized-test scores. Parents of college-bound high-schoolers go to great lengths to help their kids gain admission to top schools.

Add it all up, and you have a tutoring industry that serves millions of students and pulls in more than $4 billion annually. In each of the past three years, consumer spending on
tutoring has increased 7 percent to 10 percent.

Choices for students and their parents abound.

The biggest players in the college-prep industry, Kaplan and Princeton Review, provide one-on-one, small-group and classroom tutoring. Companies such as Huntington
Learning Center, Kumon North America and Sylvan Learning have operated storefront tutoring centers for decades, and now many of them are expanding into online instruction.

And, of course, there's no shortage of independent tutors willing to visit clients' homes.

The growing at-home market has caught the attention of established franchisers such as Sylvan, as well as start-ups such as Tutor Doctor, which is seeking entrepreneurs with a
desire to change the lives of children in their communities -- and "at least $50,000 liquid capital to invest."

Rates for K-12 tutoring typically range from $15 to $50 an hour, said Columbus Parent Magazine columnist Rashaun James, a licensed teacher who runs a tutoring business

from her home. Courses to prepare students for college entrance exams can cost $1,000 and up.

With so many options available -- and so much money on the line -- how can consumers make smart decisions?

James said parents need to research credentials, check references and ask tough questions. Among her suggestions: "What is your background? What are your past
successes? How can I tell, from you, that my child is learning?"

And perhaps the most important: "When should I expect to see a big difference?"

Results came quickly for 9-year-old Evan Elsass. And he has proof.

"I get better grades in school and on my report card," he said.