# Should Students Use Calculators in the Classroom?

Well, what do you want to accomplish? If your goal is for students to compute answers quickly and accurately, then your answer probably should be no. For instance, what would you gain by allowing students to use calculators on timed division worksheets?

But if your goal includes understanding, calculators can powerfully remedy this by helping students visualize mathematical patterns. While students are often very competent with pencil-and-paper procedures, far too many have a shallow understanding of these procedures. Furthermore, if your vision of the mathematics classroom extends beyond pencil-and-paper skills to the realistic application of mathematics, then calculators can be very helpful.

A bonus is that calculators can help to generate a significant, mathematical discussion. When is the last time you were part of a mathematical discussion—not how to compute something but a discussion of how various choices change the outcome?

## An example for upper-elementary school

With technology such as basic calculators, the horizon can open to very new and far more realistic problems. Here is one example of a real-world problem.

In America, banks follow a policy called "fractional reserve banking." While this name may sound complicated, it includes simple mathematics. But since there are a lot of computations, a calculator helps.

With this policy, American banks may lend more money than they possess. For instance, with a 50 percent reserve requirement, you could deposit $1,000 in your bank today, and tomorrow the bank can lend $500 to your neighbor. In an ideal world, your neighbor could re-deposit this $500, so the bank has another $250 to loan. Each time, the bank may loan an additional 50%.

With the teacher's guidance, students could complete the table below.

Deposited Kept by bank Loaned Total loaned 1 $1,000.00 $500.00 $500.00 $500.00 2 $500.00 $250.00 $250.00 $750.00 3 $250.00 $125.00 $125.00 $875.00 4 $125.00 $62.50 $62.50 $937.50 5 $62.50 $31.25 $31.25 $968.75 6 $31.25 $15.63 $15.63 $984.38 7 $15.63 $7.81 $7.81 $992.19 8 $7.81 $3.91 $3.91 $996.09 9 $3.91 $1.95 $1.95 $998.05 10 $1.95 $0.98 $0.98 $999.02

By the tenth customer, roughly how much would the bank have loaned from your original $1,000? Students would agree: nearly $1,000. In other words, the bank has your $1,000, it has loaned another $1,000, and so the bank miraculously doubled your money.

This gets even more interesting if the "fraction" is lowered to 10 percent.

Upper-elementary students can understand the basic idea of fractional reserve banking with only a simple calculator. Following your lead, they would not be unduly challenged to complete a similar table. More importantly, they would learn something of our national economy plus an important phenomenon in mathematics.

Reprinted from Teacher to Teacher, December 2000.