NEW YORK — The lighter, slimmer, cheaper new version of Barnes & Noble’s e-reader has a black-and-white touch screen and aims squarely at the “grandma” demographic.

And the latest Nook’s price tag — $139 — is a sign that the book seller is ready to compete with Amazon and Borders Group on e-reader prices.

Some industry watchers were expecting Barnes & Noble to unveil a device closer to a tablet computer. But the new Nook’s focus is simplicity and long battery life — the battery can last up to 2 months, said CEO William Lynch at an event in New York to announce the device.

He told a crowd of bloggers, news media and analysts that the latest version of the Nook was inspired by feedback from readers craving simplicity — specifically one letter asking no e-readers were suitable for a grandma.

“The Kindle 3 has 38 buttons. That’s 37 more than the all-new Nook,” said Lynch, taking a jab at Amazon.com’s best-selling e-reader.

The new Nook, to be available June 10, has a 6-inch touch screen and can hold up to 1,000 digital books.

Barnes & Noble Inc. executives said Tuesday that it lets readers look up words, highlight passages, search and adjust font size by typing on an on-screen keyboard. The device weighs 7.5 ounces, 35 percent less than the first Nook, which launched a year and a half ago. The iPad 2 weighs more than 1.3 pounds, nearly three times as much.

The newest Kindle weighs 8.5 ounces but holds more than three times as many books as the new Nook.

The All New Nook is Barnes & Noble’s answer to cheaper e-readers from both Amazon.com Inc. and the beleaguered Borders Group Inc. Borders and its Kobo partner said Monday that they are taking preorders for a $130 e-book reader that launches in early June.

Amazon, meanwhile, dropped the price of its Kindle last month by $25 to $114, though with a catch: The new Kindle with Special Offers includes advertisements on the bottom of its home screen and on screen savers.

Shares of New York-based Barnes & Noble rose 40 cents, or 2.2 percent, to $18.99 in late morning trading Tuesday.