# GMAT Math Knotes

## 21 terms · Very useful GMAT Math knotes compiled from various sources.

### What are the properties of evenly spaced sets?

1) The median and the mean are the same.
2) The median or mean is the average of the first and last terms.
3) The sum of the elements in the set is equal to the number of elements times the mean.

### How do you calculate the number of elements in a set when only first term and last term are known?

(last term-first term)/increment + 1

### When is the average of evenly spaced sets, an integer?

When the terms of the set are odd

### What do you mean by - 'The sum of k integers in an evenly spaced set is divisible by k'?

It means k is an integer and k is odd.

### What is the factor foundation rule?

Every number is divisible by all the factors of its factors

k=3

k=2

### What is the relationship between the exponent of positive bases and rate of increase?

The greater the exponent, the faster the increase.

### What do even exponents do to the base?

They hide the sign of the base.

### What are proper fractions?

Fractions between 0 and 1

### What happens to proper fractions as its exponents increase?

Their value decrease.

### What happens when you raise an exponent with another exponent?

You basically multiply both exponents together

### What happens to the exponents when you divide two terms with the same bases?

The exponents minus each other.

Value is one.

### How do you use hidden constraints to identify the correct solution to problems? e.g. Kelly received 1/3 more votes than Mike, what is total no of votes?

"Vk = Vm+1/3Vm. Vt = Vk+Vm = 7/3Vm. This means that the numerator has to be a multiple of 7 and should be divisible by 3 since votes are whole numbers."

x=1.25y

### How do you identify a number is divisible by 4?

When it is divisible by 2, 2 times or the last 2 digits is a multiple of 4

### How to identify a number is divisible by 6

When it is divisible by 3 and 2

### How to identify a number is divisible by 8

When it is divisible by 2, 3 times or the last 3 digits is a multiple of 8