## domingo, 27 de marzo de 2011

### Math Is for EveryoneTweet

Math Is for Everyone

MATH is not just for scientists. It is for all of us. When you shop, decorate your home, or listen to the daily weather report, you are using or benefiting from mathematical principles.

Many people seem to feel that math (or, maths) is boring and unrelated to their everyday life. Do you feel that way? Let us examine how useful, accessible, and fascinating math can be.

A Shopping Trip

Imagine you are out shopping and you come across a big sale. An item with an original price of \$35 has been marked down, or reduced, by 25 percent. That sounds like a bargain. But what is the new price? Arithmetic* comes to your rescue.

First, subtract the markdown percentage from 100 percent, and you get 75 percent (100 percent − 25 percent = 75 percent). Then multiply the original price by the result, in this case 75 percent (0.75). The new price would be \$26.25 (35 × 0.75 = 26.25). Now that you know the final price, you can decide just how good the sale really is.

What if you did not bring a calculator with you? Perhaps you can work out the answer in your head. For example, say that an item originally priced at \$45 has been marked down by 15 percent. Here is a tip for figuring percentages in your head. Use 10 percent as a base. To figure 10 percent of a number, you divide the number by 10. That is relatively easy to do in your head. Then, since you know that 15 is equal to 10 plus 5 and that 5 is exactly half of 10, you can quickly calculate the final sale price by addition and subtraction. Let us try that.

Since 10 percent of 45 is 4.50, 5 percent of 45 will be half that amount, or 2.25, and 15 percent will be the sum of those two figures, or 6.75 (4.50 + 2.25 = 6.75). Finally, we subtract 6.75 from 45 to arrive at the discounted price of 38.25 (45 − 6.75 = 38.25). Incidentally, you can use a similar approach to figure out the amount of sales tax on an item or the amount of tip to add to your bill at a restaurant. Of course, in these cases, instead of subtracting, you would add the result to the original price.

Be careful, though, not to jump to wrong conclusions when figuring in your head. A dress or a pair of slacks whose price has been discounted by 40 percent and then slashed again by another 40 percent has actually been reduced in price by only 64 percent, not 80 percent. The second discount is taken on the reduced price, not the original price. It might still be a bargain, but it is good to know the facts.

There are problems, though, that arithmetic alone cannot solve. Fortunately, many other math tools are available.

Decorating at Home

Let us say that you need to replace the flooring in your apartment and you are working within a tight budget. Before you go to the store, you first sit down to figure out what you need. The biggest question is, How much flooring should you buy? Understanding some basic geometry can help.

Flooring is often sold based on how many square units it will cover. A square foot, for example, is one foot long and one foot wide. Before you can determine how much flooring you will need, you first have to figure out how much floor area there is in each room and hallway in your apartment. The floor plans of most buildings are made up of a number of squares and rectangles. So the following formula would help you to accomplish that: a = l × w (area equals length times width). This is the geometric formula for determining the area of a rectangle or a square.

To illustrate how this formula is used, let us say that you are putting new flooring in every room of the apartment except the kitchen and the bathroom. You measure each room and come up with a floor plan like the one shown on page 23. The squares and rectangles in the plan show the size and location of the rooms. Using the above formula, see if you can calculate how many square units of flooring you will need. Here are some hints: You could calculate the area of each room by itself and then add the results together. Or you could save some time by calculating the total area of the floor plan and then deducting the area of the kitchen and the bathroom.

The word “geometry” also comes from Greek, and it literally means “measurement of land.” It involves studying the area, distance, volume, and other properties of shapes and lines. Practical formulas exist for every shape imaginable in two and three dimensions. Each day, scientists, engineers, and home decorators alike use these formulas to figure out exactly what they need. But there is more to math than arithmetic and geometry.

Use Math Every Day

Other branches of mathematics include algebra and calculus. Over the centuries math has become a truly universal language shared by everyone regardless of culture, religion, or gender. In science, industry, business, and everyday life, math has the power to solve some of the toughest riddles we face. Whether you are trying to unravel the mysteries of the universe or balance the family budget, being able to use the language of numbers is a key to success.

So even if you hated math in school, why not take a fresh look at it now? Like any language, math is learned best through use. Try using some math every day. Try your hand at math puzzles and games. One positive experience might change the way you feel. It will certainly enhance your appreciation for the wisdom of the Great Mathematician who designed these intriguing concepts in the beginning, our Creator, Jehovah God.

* Arithmetic (a term derived from a Greek word meaning “number”) is said to be the oldest branch of mathematics. It goes back thousands of years and was used by the ancient Babylonians, Chinese, and Egyptians. Arithmetic gives us basic tools that we can use each day to count and measure the physical world around us.

G03 5/22

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