# Vocabulary – Rational and Irrational

• Number line – A straight line where every point on the line represents a number.
• Absolute value – the distance from zero to any number
• Natural numbers – These numbers are all positive and start with the number 1 and go up from there. There is no end to how big the number is
• Whole numbers – This is all the counting numbers and also the number 0. So start at 0 and count up from there. Again there is no end to how big a number can get.   It goes to infinity.
• Integers – Are whole numbers that also include all the negative whole numbers. So they are as small as -infinity and as big as infinity.Integers do not include fractions or decimals.
• Rational numbers – Are numbers that you make by dividing one integer by another integer (but not dividing by 0). They also include terminating fractions and decimals. Terminating means that it has an end.2.457 is a terminating decimal. ½ is a terminating fraction.
• Irrational numbers – Any number that is NOT a rational number. That is numbers that have a repeating fraction or decimal. Pi is a complex number. It never ends. 1/3 is a repeating fraction.
• Real numbers – All rational and irrational numbers. Real numbers are any point on the number line, so if you can plot it, it is a real number.
• Additive inverse property – A number that when added to another number you get zero.   In other words, the opposite of a number.

From Georgia Virtual Learning

http://cms.gavirtualschool.org/Shared/Math/MSMath7