She had to remember that number — her number — and recite it during roll call or the Nazis would send her to Auschwitz, and perhaps her death, she said.
Keller, now in her 80s, is one of the last remaining Holocaust survivors living in the Bay Area.
In her quiet Palo Alto home, she recounted harrowing tales of watching the Nazis swarm into her town in Poland ("like ants"), of being forced to work in munitions factories, of hearing stories of other Jews' rape and murder, of starving and sleeping on bare wooden floors in winter, of being beaten, interrogated and tortured.
She lost her faith in God, she said.
Her stories, along with five other survivors' experiences, were shared last year at the South Peninsula Yom HaShoah Service of Remembrance at Congregation Beth Am in Los Altos Hills as part of the widely observed Holocaust remembrance day.
This year's Yom HaShoah service will be held on Sunday, April 7 — under the theme: "Life and Resistance in the Ghettos" — in honor of the 70th anniversary of the Warsaw Ghetto Uprising, the famous Jewish resistance movement that drew the world's attention.
Since 2002, six survivors have been honored at the service each year, in memory of the six million Jews killed during the Holocaust. Each survivor is interviewed beforehand by a high school student picked from local schools and their stories are shared with the service attendees.
Keller recalled being "anxious" the day before the service, "but I was happy when the story came out," she said. "I had to say it. I want the world to know what happened."
Hearing and recording these stories is becoming increasingly important as the last remaining Holocaust survivors are dying out, said Steven Weitzman, Stanford University professor of Jewish culture and religion.
The service, sponsored by the Jewish Community Relations Council and local synagogues, will also feature artwork by students from the local Jewish day schools.
Music and inspirational readings have also been an integral part of the service ever since Palo Alto resident Jackie Manne, wife of late Stanford professor Alan Manne, founded it at Beth Am in the mid-1970s, inspired by writer and survivor Elie Wiesel's poem on Yom HaShoah.
This year's program will include songs based on the Warsaw uprising, life in the ghettos and the story of resistance fighters who sacrificed their lives, rendered by choirs Hashirim and Yiddish Choristers.
Also part of the service will be a modified version of the traditional mourning prayer, the Kaddish, incorporating the names of some of the Nazi concentrations camps.
Dr. Andy David, Israeli consul-general to the Pacific Northwest, will also speak at the commemoration.
In addition to honoring survivors and victims, educating the present generation is one of the main objectives of the program, said Judith Rabbie, former chair of the planning committee.
Rabbie and two other committee members accompany and guide the students during their interviews with the survivors.
"I tell the students, 'You are privileged to do this,' as they are the last generation of children who can hear the stories directly from the survivors," she said.
Rabbie, herself a "hidden child" from Hungary, was saved from the Nazis by a friend of her father's and his family who sheltered her in their home at great risk to their own lives.
"I spent Christmas there. It wasn't my holiday, but I had wonderful memories, spending it with this family," she said, adding that the children must also be told of such people who risked their lives and families to save Jews.
"My grandchildren will know my story from me as long as I am around, after that, it's gone; it's going to be books and second- or third-hand information."
Even with the dwindling number of survivors, however, not all are able to share their stories easily, Rabbie said.
For many years after the war, Charles Stevens, one of the honorees this year, shied away from talking about his experience being a hidden child in a Belgian orphanage, "so that people would not pursue it," he said.
When people asked him where he was from, he would say, "New York."
It was only in 1984 that, touched by journalist Ruth Gruber's account of Stevens' parents' experiences in her book "Haven," he felt compelled to reach out to her to share his own story.
"It was a very emotional experience for me," he said.
Attending the first international "hidden children" meeting in 1991 and later connecting with other hidden children in the Bay Area also helped him become comfortable talking about his experiences.
Survivors like Stevens and Keller have also strived to give their children a normal childhood, free from the trauma of their parents' sufferings. Keller recounted chastising a friend of hers, another survivor, for yelling at her child who wasn't eating. The friend had had no food in the concentration camps.
Keller had wanted her children to grow up "mentally healthy," she said.
Despite the difficulty in moving past the horrors they lived through, for the survivors, sharing their stories is, as Rabbi Janet Marder of Congregation Beth Am said, "one of the ways they still find meaning in their lives, and have a reason to go on."
The South Peninsula Yom Ha'Shoah V'Hagevurah, Remembrance of the Holocaust and Acts of Courage, will be held at 5 p.m. Sunday, April 7, at Congregation Beth Am, 26790 Arastradero Road, Los Altos Hills. The program is free and open to the public. More information is available from the Jewish Community Relations Council at 650-847-1715 or firstname.lastname@example.org.