The math problems at GMAT are basic from 3 areas: Arithmetic, Algebra and Geometry.
Basic arithmetic operations:
- addition (8+8)
- subtraction (8-4)
- multiplication (8×3)
- division (8/2)
- raising to a power
- finding a square root
Fraction: x/y (part/whole) x = numerator, y = denominator.
Decimals are in English indicated by a point.
Ratio: The whole in ratio is sum of all parts. If ratio is a fraction the whole is the sum of the numerator and the denominator.
Average = total sum of the items/total number of the items.
Arithmetic mean = the process of finding an average.
How to find the Median:
- first order the numbers from least to greatest
- if n is odd, median is the middle number
- if n is even, median is the average of the 2 middle numbers
Mode = the number or the numbers that occur most frequently in a list of numbers.
Range = the greatest value in the numerical data minus the least value.
Standard deviation = measures the distance between the arithmetic mean and the set of numbers.
- first, find the differences between that average and each one of the set of numbers and square each of the differences
- second, find the average of the squared differences and take the square root of this average
Frequency distribution: if a,b,c = numbers, f = frequency, av = average.
Standard deviation = √ {[(a-av) ² x f + (b-av) ² x f + (c-av) ² x f]/n.}
Exponents – multiplying, dividing, raising a power to a power, distributing.
In a percentage increase or decrease problem, you must put the amount of the increase or decrease over the original amount.
In compound interest problems, the answer will always be a larger number than it would be in a similar simple interest problem.
