Inequality: An inequality compares two values, showing if one is less than, greater than, or simple not equal to another value.   (Click HERE for a visual explanation of comparison symbols)

Operation: A mathematical process. The most common are add, subtract, multiply and divide. 

Inverse Operation: The operation that reverses the effect of another operation. (For example: Addition and Subtract are inverse operations)

Rounding: Rounding means making a number simpler but keeping its value close to what it was.

Estimate: To find a value that is close enough to the right answer. 

Prime number: have exactly 2 factors which are 1 and themselves 

Prime Factor: a factor that is a prime number

Multiples: are the result of multiplying a number. 

Factor: are integers that divide into a number without leaving a remainder.

HCF: Highest Common Factor (the greatest factor two or more numbers share)

LCM: Lowest Common Multiple (the smallest multiple shared by two or more numbers)