The New York Times recently reported on a study that found, once again, that the United States is failing to develop the math skills of its students, particularly girls, especially compared to other countries where math education is more highly valued.

Indian Math Online is a start-up that aims to take on that disparity by teaching math to American kids using techniques from Indian schools.

Bob Compton, an Indianapolis-based venture capitalist and entrepreneur who co-founded Indian Math Online, hatched the idea when he was producing “Two Million Minutes”, a documentary comparing high school education in India, China and the United States. He realized that Indian teenagers who were the same age as his daughters were three years ahead of them in math.

“If you don’t get mathematics to the highest level you possibly can in high school, your career options shrink dramatically in the 21st century,” Mr. Compton said. “Our society basically tells girls they’re not good at math. I was determined that was not going to happen to my daughters.”

Mr. Compton and Indian Math Online’s co-founder, Suresh Murthy, hired a team of math teachers and software developers in India to build the site and its curriculum. At first, the site was meant for their daughters, but soon friends started asking if they could use it and word gradually spread. It has lessons for students in grades one through 12 and offers several packages for $12.50 to $20 a month.

Two-thirds of the students using it are children of Indian and Chinese immigrants. Mr. Murthy’s children are an example. “He grew up in India, and he worried about his daughters falling behind in the global competition to be educated for the 21st century,” Mr. Compton said.

The site’s curriculum is based on some crucial differences between math education in India and the United States, Mr. Compton said. Math homework in India consists of math problems that students work through, as opposed to the United States, where homework is heavy on reading about math topics in a textbook. Math teachers in India have college or graduate degrees in the topic, he said. Meanwhile, most American students in grades five through eight learn math and science from teachers without degrees or certification in these topics, according to a National Academies report.

Indian Math Online gives students a diagnostic test for their grade level and then breaks down the results by topic area, such as factors or prime numbers. It sends parents a report showing the topics in which their children are strong and weak and sends students learning modules full of practice problems. It will soon add online chat and live tutoring from math teachers in India for an extra fee.

By testing specific subject areas, Indian Math Online picks up weaknesses that a typical school test would miss, Mr. Compton said. When his youngest daughter was in seventh grade, for example, she took the diagnostic test and discovered she missed every question on prime numbers. Yet she had always received good scores on school math tests.

“It identified and diagnosed a missing fundamental math concept that her teachers hadn’t noticed,” he said. “And yet, it would have caught up with her later on, and we wouldn’t have known why she was struggling.”

Mr. Compton said that children of Indian and Chinese parents use the site consistently, but American children often lose interest after a couple months. He compares math to athletics — youths must practice a bit every day to master it. “For some reason, American kids seem to be willing to put in the work with athletics, but not put it in with the one subject that’s going to matter more to their lives than any other activity.”