Marching behind gray helium balloons, which meant he was among those representing "multi-issue groups," 74-year-old Abraham Kaufman yesterday pushed his wheelchair-bound wife, Ida, down Constitution Avenue, sweated without complaint and gazed approvingly at the sea of banners and pennants surrounding him.

In front of Kaufman and his wife were marchers wearing red "World Solidarity" suspenders. Beside him was a sign demanding: "Feed the People, Not the Pentagon." Off to the right, Hare Krishnas were dancing on the sidewalk. To the left walked a sober-faced man with a sign that said, "Find me a job, let me pay taxes and leave me . . . alone."

"This coalition here today is a little too broad to last forever," Kaufman said, struggling to keep his wife's wheelchair from rolling too fast. "But it should last long enough to force the Reagan administration to be sensitive to our demands. This march says they have to be sensitive, whether they want to or not."

With their common dream splintered over two decades into scores of noble causes, 250,000 marchers occupied Washington yesterday with the same gentleness that they, their fathers and their leaders brought with them in 1963 for the march that was a turning point for blacks' rights in America.

From the beginning yesterday, when the Lord's Prayer was passed to the sparse 8 a.m. crowds in 10 languages, it was clear that the "Coalition of Conscience" was far removed from the civil rights march of 20 years ago when blacks were simply demanding their constitutional rights to vote, to work and to sit at lunch counters with whites.

With many aspects of a segregated society eliminated by federal and state laws and with blacks holding elective offices across the South instead of protesting in the streets, the marchers yesterday came to Washington to advocate causes ranging from nuclear disarmament to growing one's own food, from gay rights to a safe environment, from restricting the import of foreign cars to vague requests for doing good. "Caring Matters Most," said one banner.

Nearly one-third of the present population of the United States had not been born 20 years ago. So yesterday, thousands of parents brought their children to Washington to acquaint them with an era when nearly one quarter of the country had segregation as official public policy.

"I wanted the kids to see firsthand what these marches are like," said Barbara Bennett, 44, a Clinton, Md., schoolteacher who marched 20 years ago. Before she and her 15-year-old son Bradley came to the march yesterday, Bennett said he asked: "You mean you were living when Martin Luther King was alive?"

Although the crowd yesterday was about the same size as that of 20 years ago, it was far more casual in dress and far less grim, according to marchers who attended both events.

"You didn't see all the people wearing shorts last time. The other time it was formal, just like everybody was going to church," said Frederick Friday, 53, a loan analyst from Washington. "There is no one who couldn't come because of being in jail," added Carl Holman, who refused to allow his daughter Kinshasha to attend the '63 march because he feared violence.

Among the kaleidoscope of causes yesterday, condemnation of the Reagan administration as both unfair to poor people and a threat to world peace emerged as the march's dominant theme, rivaling the call 20 years ago for equal rights for blacks.

In the morning, in front of the Washington Monument, the gentle crush of people laughed and clapped along with Pete Seeger's revised version of "This Old Man," which referred to President Reagan in verses such as, "This old man, he plays seven, big business is in hog heaven." Comedian Dick Gregory excoriated "that boy in the White House" for not being home for the march.

"We consider Reagan the father of the peace movement in Arkansas," said Regina Groshong, an anti-nuclear activist who rode a bus north from Little Rock.

At 11:40 a.m., comedian Bill Cosby called on the marchers to walk toward the Lincoln Memorial, following balloons color-keyed to their cause.

"Brown -- gay and lesbian -- break to the right behind dark blue," Cosby intoned in the little boy voice he uses in Jell-O commercials. "Beige is peace, you will break to the left behind red solidarity international ."

Tens of thousands of marchers failed to locate the proper balloons and marched in a happy hodgepodge of causes. Jewish activists marched shoulder to shoulder with gays; farmers walked with feminists.

Not all the blacks at the march yesterday were convinced that their problems had yet been sufficiently solved for the march to emphasize causes ahead of civil rights.

"The only thing that bothers me is that the priority list has changed. Back then we was taking about freedom and jobs. Now I see that freedom is down the list," said Maddie Hopkins, 65, a retired black schoolteacher who rode 14 hours Friday night to be in the march.

"If the racism and discrimination is going to continue, I'd rather see them blow the whole damn world up," Hopkins said bitterly.

Most marchers, however, agreed that while their demands were vague, the sum of them was broad enough to attract far more support than the somnolent civil rights movement.

"You see, everybody in this country has a cramp and a hurt," said Hugh Holland, a retired teacher from Northeast Washington. "But you see, if you tell someone you are interested in their hurt, then you all do a little better."