“Last year, I did not like math at all,” she said.

Garcia said she understands math concepts more easily when she views the tutorials.

“If you don’t get something, you can keep watching the video until you get it,” she said.

Now, when she solves problems correctly and gets high scores on her first try, she said, “it’s fun.”

Sometimes, when the bell rings, Ruggiero said, students linger to work on more problems, and “I have to fight to get them out of the room.”

At St. Mary’s, Khan Academy lessons are being used by grades 5 through 8, and administrators are considering adding it to the fourth grade.

Quincy Catholic Academy started out using the videos in grade 5 and 7 math classes this fall, and because it has been received so well, the school has expanded their use to grades 6 and 8.

“The kids are so enthusiastic about it,” said Catherine Cameron, principal of Quincy Catholic. “We’re really excited.”

The approach of showing videos during class time and encouraging students to do some work online at home is an example of what educators call “blended learning.”

Khan Academy started a pilot program in 2010 with a few classrooms in the San Francisco area, and has partnered with about 15 additional school districts since then. Khan estimates that thousands of schools are using its free resources.

The Massachusetts education agency does not track exactly how many schools are using online resources.

One of the most common providers of online education in the state is the VHS Collaborative (formerly known as Virtual High School Global Consortium), which is headquartered in Maynard and has been around since 1996.

Education department spokesman J.C. Considine said about 202 schools (representing 64 percent of the state’s middle and high schools) had more than 6,200 students participate in VHS online courses during the 2011-2012 school year.

“Blending learning still appears to be sporadic and more common in districts that prioritize investing in technology to achieve more digital resources and more personalized learning for students,” he said.

Lisa Fasano, the principal at St. Mary’s, said she is enthusiastic about using Khan Academy for math, but also tempers the expectations for this new teaching tool.

“The technology may have replaced a textbook,” said Fasano.