There was a time when the biggest quiz in American history was remarkably terse. Among the six questions were ones asking for the names of free white males and females and names of slaves.

That was in 1790, when Thomas Jefferson sent U.S. marshals to take the census.

Today, computers, printed forms and an army of temporaries have replaced the U.S. marshals for a $1 billion-plus effort to find all of us and all about us.

Riding on the findings are the apportionments of federal, state and local legislatures and the allocation of $50 billion in U.S. programs.

The big envelopes with the 1980 census questions inside are scheduled to arrive in 86 million American homes on March 28, to be filled out and returned on April 1. Those who fail to answer will be visited by one of 270,000 census-takers trained to coax recalcitrant or negligent citizens.

The census questions themselves have changed with the times. This year, bowing to feminist sensibilities, the census is dropping the reference to head of household; instead any adult may be listed first. Under pressure from Hispanics who say their numbers are underestimated, everyone this year will be asked if they are of Hispanic descent. But the census won't inquire whether you have a television -- practically everyone does.

This year, 80 percent of households will be asked 19 questions on personal characteristics and housing. One out of five homes will get a longer form which, for a family of four, would require 320 answers -- a process the U.S. Census Bureau claims will take 45 minutes.

There are the predictable questions: age, education, income, marital status (this time with a new category, "partner," for people consorting out of wedlock).And there are other detailed inquiries: Is there a passenger elevator in this building? How many bathrooms do you have? Do you have air conditioning? What is the annual premium for fire and hazard insurance on this property? Which fuel is used most for cooking? How many babies (have you) ever had? How well does this person speak English?

Census officials insist that every question is needed to implement various federal laws; the elevator question for instance, to provide services for the elderly. Information on babies born is used for welfare and the Social Security Administration, English language data for the Voting Rights Act.

But the figures, in many cases, are particularly interesting to businesses. Plumbing equipment companies want to know the number of bathrooms in each town, among each ethnic group, to help them plan production and marketing.

For all the fanfare, the census will produce few surprises when most of the results are tabulated and released next year. Trends since the 1970 census have already been documented in annual surveys. The population has grown to 222 million -- a 9 percent increase -- the smallest growth in history except for the Depression years.

But the number of households has increased twice as fast as the general population. Nonfamily households, many of them women living alone, increased 60 percent. Women are marrying later, having fewer children and entering the labor force in unprecedented numbers.

The 1980 census will document the continuing movement out of northeastern and midwestern industrial states to the South and West.

People are still moving from cities to suburbs. Some 106 congressional districts lost population in the decade -- most of them in big cities such as New York, Chicago and Los Angeles. Four of the biggest population losers are represented by black members of Congress whose political fortunes could suffer if their districts are diluted with suburban voters.

The current census, which will produce 3.3 billion answers, at least 300,000 pages of statistics and 5,000 miles of microfilm, is a far cry from the simple enumeration called for by the U.S. Constitution.

The 1980 census is the most massive statistical endeavor in history. It will touch 86 million households in a small, perhaps annoying way: yet another government form to fill out.

More than any previous headcount, this 20th decennial census will lead to dramatic shifts in political and economic power nationwide.

Some $50 billion worth of federal programs a year, mostly enacted since the last census in 1970, are keyed to census numbers. Cities like Washington and Baltimore, which lost population in the last decade, could find themselves with less revenue-sharing money, employment aid and school lunch money.

The census will be used to redraw the nation's political boundaries, for the House of Representatives, for state legislatures, and even for city and county councils. The result will be a significant shift in power from the Northeast and Midwest to the South and West; from cities to suburbs.

The South and West are expected to gain 14 congressional seats after districts are redrawn from census data. Florida is likely to get three seats, California and Texas two each. New York may lose four seats; Illinois, Ohio and Pennsylvania two each.

Printing plants have worked round the clock since last spring to produce 160 million forms -- from 5,000 tons of paper and 85 tons of ink; enough, laid end to end, to stretch around the earth's equator 1 1/2 times. Some 65,000 cardboard desks and 128,000 lend pencils have been shipped to 409 new offices around the country.

What the bureaucrats aren't boasting about is their stream of logistical foulups. Last summer, fire sprinklers flooded half the census computers. Last month, 2 million labels were stuck off-center in a Nebraska plant, requiring officials armed with knives and rubber cement to fly in from Washington to make repairs.

Top bureau officials have resigned under pressure. Congress has been up in arms over how patronage jobs were awarded. Cities are furious over the scuttling of plans to allow them to review address lists. The bureau is having a hard time recruiting 1.3 million qualified people for its pool of workers.

Seven years in the works, the census will cost more than $1 billion -- $4 per person -- quite a boost from the $220 million price tag in 1970.

In 1970, the bureau missed an estimated 2.5 percent of the population. A few city cul-de-sacs, a hidden country hollow or two can make a big difference: ffewer than 250 people determined whether Oregon or Oklahoma got an extra congressman in 1970. Oklahoma did.

So on T-night (transient) this year, March 31, census takers will visit hotels, motels, YMCAs and campgrounds to count transients. A week later, on M-night (mission), they will seek out people in missions, flophouses, jails, all-night movies, bus and railroad stations.

Test censuses have been held in Austin, Oakland, Richmond, lower Manhattan and Camden to test questions and counting methods. Some 35,000 temporary workers, armed with 90,000 special maps, personally checked 34 million addresses through Harlem alleys, West Virginia mountains, across Death Valley, in American Samoa. They explored boxcars and warehouses and took boats to find out if tiny islands were inhabited.

Alaska census workers have already started counting heads in the bush before the Eskimos take to their spring fishing camps.

"Everyone wants data to understand who they are, where they are and how they can get their share of political and economic equity," said Daniel B. Levine, deputy director of the Census Bureau. "All these goodies come from the census."