… my question is this: is there a clue in any given problem as to which formula must be used?

Sometimes. Sometimes not.

For example, if a word problem involves moving objects, and it asks for a distance, or an amount of time, or a rate of travel, then the formula Distance=Rate·Time will probably be useful.

With some exercises, the student must

*create* a formula (i.e., an equation) because we don't have formulas (to memorize) for covering every possible scenario.

For example, a taxi meter has a drop charge of $2.50 and adds $0.35 per tenth mile, with $36 per hour added for waiting time. A customer pays the driver $17.49 total. How many miles was the trip, if the taxi waited a total of seven minutes at traffic lights and the customer gave the driver a 20% tip? We don't memorize formulas for this type of exercise; it's easier to just work it out, in steps.

Word problems in algebra almost always require writing an equation, followed by solving it. To write an equation, one must think about the given information, and determine two quantities that are equal. Writing these quantities as algebraic expressions comes from first assigning symbols to represent unknowns (especially the unknown for which the problem asks).

In my opinion, when math students lack confidence going into an exam, it's often because they have not practiced enough outside of class. With more practice comes more exposure to different types of word problems. With more exposure comes greater pattern recognition and recall.

At the University of Washington, the math department recommends studying five hours outside of class for every one hour of class attended, to be successful. Most math courses are three hours per week, in class. That means 15 hours per week studying outside of class.

I'm glad that you're taking an active interest in your child's education. With a lot of practice, things do get easier. Encourage your child to keep trying; they will know when they feel confident.

"There are no shortcuts to any place worth going." ~ Helen Keller :cool:

PS: We're also here to help, with specific exercises. If your child gets stuck, have them post the complete exercise statement (in a new thread) and show whatever work they can.