Ignoring a tempting proposition, Miami area voters today handily defeated a nearly 100 percent cut in their county-wide real estate taxes, a slash that officials said would have decimated county services.

With almost all the county's 462 precincts counted, nearly seven of every 10 voters had cast their ballots against the bizarre tax cut proposal, the result of a mathematical mistake by proponents.

So ended 11 months of tax-cut efforts by a Coral Gables retiree, Harry L. Wilson, and his Dade Tax Revolt group. They started out seeking a 50 percent cut in the county-wide property tax rate. But they goofed, miscalculated, misworded petitions signed by 15,000 voters and forced instead today's referendum on a skinflint's dream: a 99.95 percent cut in the tax rate.

During the voting today, opponents of the tax cut-- basically business and labor groups-- had expressed fears that, despite public opinion polls giving them a good lead, there would still be too much public frustration out in the precincts.

And anger there was. Voter interviews uncovered a seething layer of discontent with the Dade County metropolitan government, the well-financed organizations that opposed the tax cut, and a general, unidentified collection of people referred to by one voter as "freeloaders."

"I don't think it's a mandate, a vote of confidence in anything," said Robert Floyd, a former Miami mayor who headed one anti-tax-cut organization. "There is unrest."

"I voted for it, I'm sick and tired of all the damn freeloaders in Miami," said Jayne Davis, a Miami resident, shortly after she cast her ballot at the St. Michael the Archangel Church. "I can remember when we didn't have any freeloaders."

Voters expressed disbelief in claims by tax-cut opponents that residents would experience severe cutbacks in such services as police protection.This week, Miami newspapers were loaded with half-page ads, such as one from a labor-funded Taxpayers Committee To Save Our Services: a policeman in the ad gently holds an injured child next to a headline reading, "Some call him pig. Call him what you will Vote against the tax referendum or you won't be able to call him at all."

In the end, even after being outspent 100 to 1 for ads such as that and faced with the problems posed by their mathematical error, tax-cut proponents still garnered about 35 per cent of the vote.

The error came about when petition drafters expressed a desired tax rate as "4 mills per $1,000," compared to the current rate of 8 mills. If the petition had simply said 4 mills, the proposed tax rate would have been $4 for each $1,000 of property valued. But 4 mills per $1,000 means a tax rate of a scanty $.004 for each $1,000.

That is not much of a tax, and county officials responded that it would not have left much in the way of county-wide services: 22,000 street lights permanently shut off along 400 miles of main road, reduced robbery and homicide investigations, reduced police patrols, a county jail closed with prisoners released prematurely, two nursing homes closed, and eight of every 10 buses taken off the streets.

The county work force of 14,000, excluding such propertiary employes as the seaport and airport authorities, would have been cut by 9,000. Pink slips had already been prepared.

The reduction of service would have been far greater than the savings to homeowners, because residents would have continued to pay other levies for schools, libraries, flood control and the like.

Two groups-- one primarily labor and funded heavily by the American Federation of State, County and Municipal Employes and another primarily business and professional firms-waged a battle against the referendum that cost more than $200,000. Wilson's group; according to the finance report, spent little more than $2,000.

He had argued that the county and its 17 municipalities could survive the one-year tax cut, and accused officials of allowing the accidental 99.95 percent cut to go on the ballot in hopes that it would be easier to defeat than a 50 percent cut.