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

Increasing : Increasing means getting bigger.

Nearest ten : Rounding to the nearest ten refers to rounding such that the resulting number is a multiple of ten. If the ones digit is 5 or more the tens digit is rounded up, otherwise it is rounded down.

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

Ones digit : The first digit left of the decimal point (or the digit furthest to the right if there is no decimal point). It counts multiples of 1.

Round : Round can be a property of a shape, meaning that it does not have any corners. For example a circle can be described as round. A number can be informally described as round if it does end in one or several zeros such that rounding that number to a certain number of digits does not change the number.

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.

Tens digit : The tens digit is the second digit left of the decimal point. For example 31.2 and 32 both have tens digits equal to 3.

Equation : An equation is a mathematical statement in which two expressions are written with an equal sign in between. A solution of an equation is a set of variables that makes the statement a true statement.

Factor : If a natural number is divisible by a second natural number, that second natural number is called a factor of the first natural number. For example the factors of 12 are 1,2,3,4,6 and 12.

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

Positive : Positive means $\geq 0.$

Product : A product is the result of a multiplication.

Solution : A solution to an equation is a choice of variables that when substituted into the equation results in a true statement.

Zero : The number 0.