Count : To count means to find out the number of objects by adding one for every object.

Decimal point : The point in a decimal separating the digits representing multiples of wholes from the digits representing fractions of wholes.

Hundredth : Hundredth refers to the number $\frac{1}{100}=0.01=10^{-2}.$

Tenth : Tenth refers to the number $\frac{1}{10}=0.1=10^{-1}.$

Thousand : Thousand refers to the number $1,000=10^3.$

Thousandth : A thousandth refers to the number $\frac{1}{1,000}=0.001=10^{-3}.$

Expression : An expression is a succession of constants, variables and mathematical operations that if evaluated for specific values of the variables represents a number.

Variable : A letter in an expression or function that represents an arbitrary number.