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

Number : A number $x$ is a mathematical symbol representing a quantity.

Addition : Addition is the mathematical operation that describes increasing a number by an amount equal to a second number. The mathematical symbol for addition is the plus sign $+.$ The term addition is also used for a generalization of this basic operation on numbers to functions, vectors and matrices.

Zero : The number 0.

Decimal : A decimal is a number represented by digits in front and after a decimal point. In front of the decimal point the digits are the ones digit, tens digit, hundreds digit and so on. After the decimal point there are the tenths digit, hundredths digit, thousandths digit and so on. For example the decimal 1.3 can be written as $1\frac{3}{10}.$

Digit : A digit is a symbol used in the representation of a number.

Division : Division is the mathematical operation that divides objects equally into groups. More generally $x\div y$ is defined as the number that if multiplied by $y$ equals $x.$

Hundred thousand : Hundred thousand refers to the number $100,000=10^5.$

One seventh : One seventh is the number $\frac{1}{7}=0.\overline{142857}.$

Remainder : In the division of a whole number $x$ by a natural number $y$ the remainder is the unique whole number $r$ with $0\leq r\lt y$ with $x=m\cdot y+r$ for some whole number $m.$ The remainder is the number of leftover wholes in the division. For example the remainder of the division of 14 by 3 is 2 as $14=4\cdot 3+2.$ Remainders are fundamental for the concept of congruence modulo $y$ in number theory.

Rounding : Rounding is the operation of changing a number to a number that is close to the original number. Rounded numbers are often used to do quick rough calculations for estimation purposes. For example rounding $4549$ to the nearest thousand results in 5000, rounding the same number to the nearest hundred results in 4500. In general one rounds up if the digit after the digit we try to round to is 5 or more, otherwise one rounds down.