# lect. 1&2 key terms MATH2213 textbook project

Term Definition
counting numbers the most basic numbers; the set of numbers that we use to learn how to count; also called "natural numbers"
cardinality of a set the number of things in a set
one-to-one correspondence necessary to know before a child learns to count; being able to match one object to one other object
base-ten system the system we use to write and say counting numbers without having to create new symbols; also called "decimal system"
digit the ten distinct symbols, or numerals, from 0-9, that are required to use in a base-ten system
base-ten representation a string of digits that represents a number, such as 1234; also called the "base-ten expansion" of the number
expanded form writing numbers in this form shows how a number is composed of its base-ten units
base-ten units a string of digits stands for the total amount that all its places taken together represent and within this string, each digit stands for that many of that place's value
whole numbers the counting numbers together with zero
number line a line on which one location has been chosen as 0, and another location, to the right of 0, has been chosen as 1; stretches infinitely far in both directions
numeral a figure, symbol, or group of these denoting a number
tally system uses hash marks as a form of numeral used for counting; most useful in counting or tallying ongoing results, such as the score in a game or sport, as no intermediate results need to be erased or discarded
egyptian system a system of numeration based on the scale of ten, often rounded off to the higher power, written in hieroglyphs, but without a place-value system
place value the numerical value that a digit has by virtue of its position in a number
landmark numbers numbers that are easy to compute with