For 1990, each personal and dependency exemption is worth $2,050, up from $2,000 last year.

Personal Exemption

If you can't be claimed as a dependent by your parent or someone else, you are entitled to take a personal exemption for yourself.

This personal exemption is the same for all nondependent taxpayers. Taxpayers who are 65 years or older or blind get an addition to their standard deduction.

You can claim your spouse on your separate return only if your spouse does not file a return, has no income and cannot be claimed on someone else's return. Exemptions for Dependents

There are five tests that must be satisfied to qualify as a dependent. In general, a dependent must be related to you, have gross income of less than $2,050, have more than half of his or her support provided by you, not file a joint return with his or her spouse, and have been a U.S. citizen or resident alien.

The booklet on Section 4, line 6c fills in the gaps in applying these rules in different circumstances. Here are a few:

Relationship or member of household test: Virtually any lineal descendant or ancestor -- see the list in the booklet -- will qualify as your relative, including adopted children and in-laws. Once the relationship has been established, it is not ended by death or divorce.

For example, if your late wife's mother meets the other tests, you may claim her as your dependent after your wife dies -- even if you have remarried.

A person who lives in your home for the entire year as a family member, but not in violation of any local law, can also meet the relationship test.

Income test: In assessing the $2,050 income limitation, do not count bona fide gifts or income not subject to tax, such as nontaxable Social Security benefits.

Also, do not count income earned by a permanently and totally disabled person in a sheltered workshop, which income is incidental to the dependent's rehabilitative care and training.

The income test is waived for a child who at year end is either under age 19 or a full-time student under 24. The instructions amplify who is considered a full-time student.

Support test: The support test is based on the amount of cash actually expended by the taxpayer, the dependent and third parties, such as a grandparent, for the support of the dependent.

The taxability or nontaxability of the money so used doesn't matter.

You must have provided more than half of the support for a dependent during 1990, except for special circumstances involving children of divorced or separated parents and multiple support agreements.

Support includes the costs of most personal living expenses, such as food, shelter (for example, the fair rental value of lodging), clothing, education, medical expense, recreation and transportation, including the cost of an automobile.

Certain items aren't considered support, including income and Social Security taxes paid by the dependent on his own income, scholarships and life insurance premiums.

If you provided separate living quarters for the dependent, such as an apartment for an elderly parent, count the cost of that housing. But if your dependent lived rent-free in quarters you owned, then use the fair market value based on comparable housing, rather than the cost.

Joint return test: Although a married dependent cannot generally file a joint return and still qualify as your dependent, a married person who files a joint return solely to claim a refund of taxes withheld still may qualify.

You also may be able to claim an exemption for a person whose spouse files a separate return and doesn't claim that person as his or her dependent.

Special rules for children of divorced parents: For a divorce or separation agreement executed after Dec. 31, 1984, or for earlier decrees if modified after that date, the custodial parent automatically gets the dependency exemption for a child, regardless of which parent provides the support, as long as both parents together provide more than half the child's support.

For couples who were divorced or separated before Jan. 1, 1985, and who haven't modified the original decree after Dec. 31, 1984, the noncustodial parent can take the exemption if the decree so stipulates and if that parent contributes at least $600 for the child's support in 1990.

Check the "pre-1985 agreement" box on line 6d on Form 1040, if this is the case.

In any event, the custodial parent may waive the exemption in favor of the noncustodial parent by signing Form 8332 "Release of Claim to Exemption for Child of Divorced or Separated Parents," which the noncustodial parent should attach to his or her return.

Note, however, that by granting the waiver, the custodial parent does not lose other tax benefits and still may be able to claim head-of-household filing status, the earned income credit, and child care credit.

Joint Support

Several people may jointly support a dependent, such as siblings sharing the cost of caring for a parent, with no single person contributing more than half of the support.

If together you contribute more than half, one member of the group may claim the exemption if he or she provided at least 10 percent of the total and the others agree.

Each year a different taxpayer may claim the exemption, so it may be rotated from year to year.

Each eligible contributor must sign an IRS "Form 2120 Multiple Support Declaration" agreeing to the arrangement; the taxpayer claiming the exemption must then attach all the signed Forms 2120 to his or her tax return.

Social Security Number

If you claim as a dependent a person who is 2 years or older, be sure to enter that person's Social Security number on the line 6c, along with his or her name, on Form 1040 or 1040A.

If your dependent does not yet have a Social Security number, you should apply for one by filing Form SS-5 with a local Social Security Administration office.