LEXINGTON — Investing is a tough decision for any adult. There’s an endless assortment of 401Ks, stocks, mutual funds, IRAs, real estate possibilities from which to choose. Where to put your dollar so that later on in life you and your children will have a secure future? It’s a tough question — if you ask a hundred experts, they’ll each offer you a different answer.

Still, the decision is even more difficult to make for children. Comprising about 3% of the investment market, children spend close to nine hundred million dollars a year on different kinds of investments.

“Unfortunately there’s a lot of charlatans out there who try and lure children into bad investments,” said Mrs. Jacobson, a fifth-grade teacher at Lexington’s Harrington Elementary School.

Belmont PTA president Laura Dawitz concurs. “There’s a man who will come by the junior high in a van,” says Dawitz. “He’ll try to sell marshland in Florida, blue chip stocks, that sort of thing. It’s very tempting for children. They see a way to make a quick ten thousand dollars — and that comes to a lot of Beastwars, Transformers and SweeTarts. The kids often go for it, especially the fat ones that everyone picks on.”

What sort of thing can be done to prevent your child from falling for this trap? Harvard professor Donald Clasp, who has Ph.Ds in both child psychology and economics, says there are a few simple rules that parents should teach their children.

“One thing that children should be aware of is that no one needs marshland in Florida. Another common trick is to try and get children to invest in pork bellies around Christmas time. Many children have fond memories of the film Trading Places and are looking for a way to transfer the confidence of Eddie Murphy’s character onto themselves. Child brokers know this, and prey on it.”

In the end, the important thing to remember is that constant supervision may not be enough to protect your child from bad investments. “You are safer to tell them to say ‘No!’ in a loud voice, and then get the dickens away,” said Clasp. “Most so-called ‘schoolyard brokers’ are reluctant to leave the safety of their van to chase a potential victim.

“Remember,” said Clasp, “in today’s hyper-volatile market, any investment your child makes could be their last.”