The formula for calculating intelligence quotient is

Chronological Age and Mental Age

Chronological age (CA) is a measure of an individual's age based on the calendar date on which he or she was born. Chronological age is calculated on most psychological tests. It is measured in days, months and years.

Mental age (MA) is a measure of an individual's mental attainment based on the chronological age at which an average individual reaches that same level of attainment.

Imagine that you are working with a pair of 11-year-olds who were born on the same calendar date. You notice that one student is intellectually gifted and can read and do math at a college level. Their intellectual capabilities are that of a 19-year-old, while the other 11-year-old has the intellectual capabilities that an average 11-year-old would have. This is what is meant by mental age.

Mental age is based on your intellectual development, while chronological age is based on the calendar date on which you were born.

Use the following guide to compute chronological age:

Example: Today’s date: 4-17-2017 Students date of birth: 5-17-2000

Set the year, month, and date as follows: (You will need to regroup months and days).

Year Month Day

4 (after regrouping) 47 (after regrouping)

2017 5 (borrow 1 month, add to days -30) 17 (add 30 days)

2000 3 19____________

17 1 2 28 (If days exceed 15,

add one month

CA = 17 years 2 months

Calculating Mental Age

Determining the difference between MA and CA is useful in designing lesson plans for the especially intelligent and cognitively impaired. You will need a standardized (i.e., WICS-IV, Stanford-Binet, etc.) intelligence quotient proven reliable.

Step 1

Procure an IQ test score that was administered by a qualified, professional (i.e. school psychologist). Write down the score in the following formula: IQ = MA/CA ÷ 100, where "MA" is your mental age and "CA" is your chronological age. For example, if your chronological age is 10 and your IQ score is 120, the formula would read, 120 = x/10 ÷ 100, where "x" is your mental age.

Step 2

Divide both sides of the equation by 100. This leaves you with 1.2 = x/10 because dividing the right side of the equation cancels out the multiplier of 100, and dividing the left side of the equation, or 120/100, equals 1.2.

Step 3

Multiply both sides of the equation by 10 to solve for "x," or your mental age. Since "x" is currently the numerator in the fraction x/10, multiplying by 10, or 10/1 to be specific, yields 10x/10, or simply, "x." Multiplying the left side of the equation equals 12, or 1.2 * 10. Therefore, x=12. So in this example, your mental age is 12.

Warnings

· Cognitive development slows at 16, then stops at 18, making the calculation of mental age irrelevant.

· IQ tests for adults use a "standard deviation" formula measured against a mean score of 100. No mental age calculation is used in the IQ scores of adults.