WASHINGTON — There are at least 3 billion apps out there, but small business owners aren’t taking advantage of them to increase sales –because they don’t know what’s available or don’t know how to use them, experts say.

“There is a huge opportunity gap in increasing possibly productivity and profitability,” Dr. Patricia G. Greene, Paul T. Babson chair in entrepreneurial studies of Babson College, said Thursday at a congressional hearing. Citing the result of a user survey by AT&T and the Small Business & Entrepreneurship Council last year, she said despite 94 percent of the polled small business owners reported using smart phone technology and 73 percent used apps for social media and marketing, but only 18 percent used them directly for sales-related activities.

Because apps are easy to use, they are easily accessible to businesses of all sizes, giving the small firms a neutralized environment to survive, Greene and others told the House small business committee.

“Local retailers can easily tap into this market using apps like Esty and EBay that serve as their storefront,” said Morgan Reed, executive director of the ACT| App Association. “These can be particularly helpful to small businesses in remote areas.” He adds that there are thousands app there that can help businesses with inventory management or customer relationship management requesting very low costs, yet the “real barrier” is that there is no knowledge.

But Greene said small businesspeople don’t know where to learn how to use the apps as a business strategy.

In addition, “there are concerns that how do I bring it back into my business, how do I train everybody who already works there, how will it fit or not fit with the tools I’m already using,” said Greene, who is leading a Goldman Sach’s entrepreneur education program that focuses on using technology to improve business operations.

David Barrett, CEO of Expensify, a San Francisco-based expense reporting company, said Congress should work with small business to provide training and awareness education.