Q. I need to find ways of dealing with a problem I'm having with my son who has just turned 4. I have another son, 5 1/2.

My 4-year-old handles his anger in a mildly destructive manner. If he doesn't get his way he is liable to throw, break or resort to inflicting injury on people -- scratching, pushing.

My practice has been to isolate him when this happens -- telling him I will not accept such behavior while making it clear I still love him.

How can I channel his angry behavior into something constructive? He is an engaging, lively, usually sweet-tempered child except for his anger, which is not frequent. I'm afraid he will grow up without knowing how to handle it properly.

A. You're so wise to want to help your child express his anger constructively, rather than suppress it. Justified or not, it can't be denied.

Children usually get mad because they really are sad or anxious or frustrated, or their self-confidence has taken a nosedive. In your son's case, any or all of these things may be true. Imagine how infuriating it would be to have a big brother who could do everything you could do, but always a little better and faster.

It's enough to make anyone throw something. Besides, this second child may be born more impatient than the older one.

Letting your 4-year-old have a few minutes to cool off is a good idea, but he should get the explanation in advance, on a day when all is well. That's when you tell him that although you love him, he will be sent straight to his room, without any discussion at all, if he tries to hurt anything or anybody.

And when it does happen, you dispatch him with a kiss, but no conversation, no matter how much he tries to engage you. This only would reward him for his rotten ways, for even though a lecture is negative attention -- it's still attention.

Instead, give him an extra hug when he's good, or say what fun he is to have around. You don't have to compare the good behavior with the bad; your actions do that for you.

You also may be able to prevent some of his anger by looking for a pattern. If it flares up at certain times of the day, he is probably hungry or tired, so you give him a high-protein snack a little earlier than usual, or let him listen to records or stories until he is ready to be challenged again.

And when he's started to whirl, but hasn't exploded yet, go for exercise. An angry child needs to use his big muscles, rather than the little ones, and to look successful no matter how he handles himself.

Running with you -- although at a very slow pace -- will help him release tension and may make him act more grown-up too, since he'll be flattered to be invited.

Bread-baking is another excellent outlet for aggression -- probably the best: The reward is so lovely.

He also can hammer some charcoal briquets into bits so you can add them to a potted plant to keep the soil sweet. There's nothing like being useful to make a child sweet too.

Q. Recently we had our ideas confirmed. Our 4 1/2-year-old daughter has a very high IQ -- 173. She gets along well with her playmates, and we have not had her in anything by Sunday school, as my husband believes children should remain in the home with their parents as long as possible.

Now we want to find the best school for her, so she doesn't get lost in the shuffle.

My husband is a professional, but our expenses almost equal his income. We could however, tighten up considerably, or I could take a part-time job, if private school were necessary.

Also, do we ever discuss this with her teachers, playmates' mothers, etc.? Or with her? With families? And what about her little brother -- a seemingly average, happy-go-lucky little guy?

A. You're doing so well it seems presumptuous to advise you. Obviously your daughter is in great shape, but worry is part of the parenthood package.

There are five areas of 'giftedness -- sports, creativity, leadership, fine motor skills and academics -- but it is the last that causes most of the psychological problems.

Since you're from Prince George's County, you may be in the Magnolia school district, which has a deservedly fine reputation for developing an excellent statewide program for the gifted. Even if your daughter is assigned elsewhere, the local public school seems best, for you don't want your child to feel different. If she tries it, she at least can make more friends before changing to a school that suits her better.

Although there are no aptitude tests designed to tell a parent where to find the right school -- and what a blessed thing if there were -- there is the Educational Counseling Associates, Inc., 3631 Ingomar Pl., NW. (686-1774). The two highly trained women who run it have evaluated the area's independent schools, many public ones and many boarding schools.

One of these women would interview your child and yourselves and recommend the school that would suit her best. It takes 5-8 hours to match the child and the school at a cost of $50 an hour. In the long run, this probably would be the cheapest, safest way to go, for a school that is right for one child may be quite wrong for another.

And as for broadcasting the abilities of your child? Don't. Her intelligence is probably fairly obvious already, but the minute you start talking about it, people subconsciously may treat her differently -- a sort of "prove-it" attitude. Teachers will know if it is on her transcript, but be sure they don't make an issue of it. It's amazing how often a teacher will say, "Now we know how smart you are. You should have the answer."

Your daughter needn't be told either -- at least for a couple of years -- and then only in a fairly casual way. Don't worry. She's going to do fine and your son, too, for you and your husband have such a complete acceptance of both children, as they are.

The child who has this approval is truly gifted.