The term percent is often attributed to Latin per centum, which means by a hundred. Actually, it is wrong. We got the term from Italian per cento — for a hundred. The percent sign % evolved by the gradual contraction of those words over centuries. Eventually, cento has taken the shape of two circles separated by a horizontal line, from which the modern % symbol is derived. The history of mathematical symbols is sometimes astonishing. We encourage you to take a look at the origin of the square root symbol! When a is a fraction, this essentially involves exchanging the position of the numerator and the denominator. The reciprocal of the fraction 3

Spherical correction (SPH): The spherical correction (SPH) refers to the lens strength needed to correct vision that affects the whole eye. This is usually the first number listed.Fraction subtraction is essentially the same as fraction addition. A common denominator is required for the operation to occur. Refer to the addition section as well as the equations below for clarification. a feet" might not mean much to you because you may want to express the decimal part, which is in feet, in inches once its is a smaller unit.

This ratio calculator will accept integers, decimals and scientific e notation with a limit of 15 characters. Simplify Ratios: The most common age-related change is presbyopia. More than one-third of Americans experience this condition, which develops as the aging eye lens becomes less flexible and stiffer. People can start developing presbyopia when they are in their 20s. Senator Homer Simpson was polling at 10% last month. He had a few successful debates since then, and now 12% of the population wants to vote for him. What's the change? You want to say 2%, are we right? It's wrong! Let's examine this. Imagine the whole population is 1000 people. 10% of them is 100. 12% is 120. What's the percentage increase? It's 100 × 20 / 100 = 20%!

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The percentage tells you how number A relates to number B. A real-world example could be: there are two girls in a group of five children. What's the percentage of girls? In other words, we want to know what's the ratio of girls to all children. It's 2 out of 5, or 2/5. We call the first number (2) a numerator and the second number (5) a denominator because this is a fraction. To calculate the percentage, multiply this fraction by 100 and add a percent sign. 100 × numerator / denominator = percentage. In our example, it's 100 × 2/5 = 100 × 0.4 = 40. Forty percent of the group are girls. That's the entire procedure of converting between decimal fractions and percentages.

If you add 3/4 and 5/8, what would be the sum? A.more than one B.equal to one C.less than one D. zero Is the ratio A : B equivalent to the ratio C : D? The calculator finds the values of A/B and C/D and compares the results to evaluate whether the statement is true or false.Eyeglass prescriptions change because people’s eyes change. Usually, these differences are not due to illness. For example, children do not fully develop the ability to focus both eyes on one object at the same time until they are 7 years old. The calculator will simplify the ratio A : B if possible. Otherwise the calculator finds an equivalent ratio by multiplying each of A and B by 2 to create values for C and D. Similarly, fractions with denominators that are powers of 10 (or can be converted to powers of 10) can be translated to decimal form using the same principles. Take the fraction 1