Open 7 a.m. until 10 p.m. Monday through Friday, noon until 11 p.m. on Saturday, and 1 to 9 p.m. Sunday. No parking provided. Credit cards accepted. Reservations requested on weekends.

If your kids rebel at being limited to a hamburger or a hot dog from the children's menu when you eat out, they'll be glad to know of a new restaurant that will serve a child's portion of just about anything on the menu. The price is generally 35 per cent less than the corresponding adult portions.

THe Monticello Restaurant, which has been at 1600 Wilson Blvd. in Rosslyn since August, offers a few Greek dishes and several seafood specialties along with the usual sirloin and filet mignon steaks.

Its atmosphere is light and airy - lattice work, pretty green booths, straw basket-weave chairs and lots of plants. It's a touch of summer in th midst of dreary winter.

Entree prices run as high as $8.50 for the lobster tail or the larger steaks, but a family looking for well-prepared food at reasonable prices in pleasant surroundings can find some genuine values tucked away in the menu.

Several of the entrees are under $5, including sauteed calf's liver, flounder, trout or sole in season, veal parmagiana, broiled chicken and baked eggplant moussaka. Slightly more are the crab imperial, beef brochette ($5.95 each) and the lamb shish kebab ($5.25).

All entrees include salad, bread and butter and a choice of baked potato, French fries, rice pilaf or the vegetable of the day.

On our recent visit there, our children ordered their usual "Shirley Temple Cocktails" and my husband and I each had a glass of the house red wine - Sebastiani burgundy.

On our tossed salads, we all had the zesty house dressing - one of vinegar and oil that is made from a recipe used by Thomas Jefferson at his Monticello.

For her main course, our 8-year-old daughter chose spaghetti. The sauce had a "homemade" taste with plenty of ground meat and none of the tomato paste flavor so prevalent in restaurant-prepared spaghetti.

Our 5-year-old son wanted chicken, and the chef, thinking that he would probably prefer fried chicken over the broiled chicken offered on the menu, prepared a special platter for him. He was right. Our son ate two of the three pieces of the breaded and crisply fried chicken in addition to his salad and French fries - more than he usually eats during an entire day.

Our waitress, too made many gestures to ensure that we enjoyed ourselves, not the least of which was taking the children to the glass carry-out window so that they could watch their dinners being prepared.

My husband was happy with the calf's liver. It had been sauteed with bacon and onions, and came to the table hot and in generous portion - a good value at $4.25.

My beef brochette was also of good quality and portion with several large pieces of broiled marinated beef on a skewer along with the usual green peppers, onions, and tomatoes.

For dessert the children had ice cream while my husband and I had coffee. Our bill came to $19.65 plus tax and tip.

On a previous visit to the Monticello, we had also enjoyed the crab imperial and fish dishes. At lunchtime, generous, well-priced sandwiches are served. The restaurant opens at 7 a.m. during the week for breakfast.