Newton's Classroom Dictionary
Below is a list of math terms used in the lessons throughout Newton’s Classroom. To return to this list at any time, click on the Dictionary button from any page.
Addition (to add): the process of combining numbers
Associative Property: the property that allows numbers to be grouped before adding or multiplying without changing the sum or product
Borrow: When you subtract a larger digit from a smaller digit, you need to borrow. In 53 - 29, you can’t subtract 9 from 3. Instead, you subtract 9 from 13 by borrowing a tens digit.
Carry: When the sum or product of two digits is greater than 9, you need to carry. In 23 + 29, the sum of the ones digits is 12, so you carry the 1 into the tens column.
In 18 x 2, the product of 8 and 2 is 16, so you
carry the 1 into the tens column.
Commutative Property: the property that allows numbers to be added or multiplied in any order so that the sum or product is the same
Cross product : a number found by multiplying the numerator of one fraction and the denominator of the opposite fraction
Decimal: a number with one or more digits to the right of the decimal point. The digits to the right of the decimal point indicate a number that is less than one whole. Some examples of decimals are 0.1, 0.75, and 4.25.
Decimal point: a symbol used to separate the ones place from the tenths place in decimal numbers or dollars from cents in money
Denominator: the bottom number of a fraction that tells how many equal parts there are in the whole or group
A common denominator is a number into which two or more denominators can be divided evenly.
The fractions 
and 
have a common denominator of 12 because both denominators (4 and 3) can
be divided evenly into 12.
Difference: When you subtract a number from another number, your answer is called the difference.
Digit: any of the numerals 0, 1, 2, 3, 4, 5, 6, 7, 8, or 9 that is used to write numbers. For example, the number 38 has two digits, a 3 and an 8.
Dividend: the number that is divided into groups
Division (to divide): a mathematical operation that determines how many groups of the same size there are in a set or collection of objects. Division is also useful for finding how many objects are in each group when a set is divided. It is the inverse or opposite of multiplication.
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Divisor: the number of times that a set or collection of objects is divided
Equivalent Fractions: fractions that have different denominators (total parts) but have the same overall value
Estimate: an amount that is close to another amount but not exact. For example, you might not know how many students are in your class, but you might think it's about 20. In that case, 20 is your estimate for how many students there are. Note: Estimate is also a verb. When you try to guess how many students are in your class, you are trying to estimate this number.
Exact: an amount that is just right; when you work with numbers, sometimes you work with exact amounts and sometimes you work with estimates. For example, if the Eagles beat the Seahawks in football by a score of 49 to 33, you can say that the Eagles scored exactly 49 points, or that they scored about 50 points.
Factor: a number that is multiplied by another number. The numbers 4 and 5 are factors of 20.
Four-digit number: a number that has four
numerals; some examples of four-digit numbers are 1,976 and 7,144.
Fraction: a number that names part of a whole or part of a group
Greatest common factor: the largest number that divides evenly into two or more larger numbers. In a fraction, the greatest common factor is the largest number that can divide evenly into both the numerator and denominator.
factors of 4: 1, 2, 4 factors of 14: 1, 2, 7, 14 The greatest common factor of 4 and 14 is 2 .
Hundreds place: is the position just to the left of the tens place. For example, in the number 296, the 2 is in the hundreds place. This means that the 2 in 296 has a value of 2 hundreds, or 200.
Hundredths place: the position in a decimal number just to the right of the tenths place or the second place to the right of the decimal point. For example, in the decimal number 0.58, the 8 is in the hundredths place. The digit 8 has a value of 8 hundredths.
Improper fraction: a fraction in which the numerator is greater than the denominator. An improper fraction always has a value greater than 1.
Least common denominator: the smallest number that two different denominators can divide into evenly.
The least common denominator of
and
is 30.
Long division: the multi-step process used when the divisor is a large number and requires each step of the division to be written out
Mixed number: a whole number followed by a fraction that describes an amount between two whole numbers
Multiplication (to multiply): a mathematical operation where a number is added to itself a certain number of times that determines the total number of items in equal groups.
Numerator: the top number of a fraction that tells how many equal parts of the whole are being considered
One-digit number: a number that is written using only a single numeral. Some examples of one-digit numbers are 5, 2, and 9.
Ones place: the position farthest to the right in a whole number. In the number 18, the 8 is in the ones place. This means that the 8 in 18 has a value of 8 ones
Percent: is a part of 100 or “per one hundred.” For example, 4 percent is 4 out of 100 or 
. The % symbol means the number is a percent. A percent which is less than 100% is like a fraction because it describes a part of a whole.
Place value: the value of a digit; when you read and write numbers, the value of a digit depends on its position:
- In the number 31, the 3 is in the tens place and has a value of 30.
- In the number 23, the 3 is in the ones place and has a value of 3.
Product: the number that results from multiplying
Proper fraction: a fraction in which the numerator is less than the denominator. A proper fraction always has a value less than 1.
Proportion: a statement that says that two fractions are equivalent. In a proportion, cross products are always equal.
Quotient: When you divide a number, your answer is called a quotient.
Reciprocal:
Two numbers are reciprocals of each other if their product is 1. For example, 3 is the reciprocal of 
.
Remainder: the number that remains or is left over when one number is not divided evenly by another number
Repeating decimal: a decimal number in which a single digit or pattern of digits is repeated. For example, 0.8333… and 0.2727… are repeating decimals because when their equivalent fractions are changed to decimals, the remainder is never 0. To show that a decimal is a repeating decimal, a bar is drawn over the repeating digit or pattern of digits.
Rounding: is when a nearby number takes the place of another number. For example, the number 29 might be rounded to 30.
Rounding down: is when a nearby smaller number is used to take the place of a larger number. For example, the number 43 might be rounded down to 40.
Rounding up: is when a nearby larger number is used to take the place of a smaller number. For example, the number 49 might be rounded up to 50.
Subtraction (to subtract): the process of taking away from a number
Simplest form: the form of a fraction in which the denominator and numerator have no common factors other than 1
The simplest form of
is
.
Sum: the number that results from addition
Tens place: is the position just to the left of the ones place. In the number 26, the 2 is in the tens place. The 2 has a value of 2 tens, or 20.
Tenths place: the position in a decimal number just to the right of the decimal point. For example, in the decimal number 0.6, the 6 is in the tenths place. The digit 6 has a value of 6 tenths.
Terminating decimal: a decimal that ends. For example, 0.35 and 1.25 are terminating decimals because when their equivalent fractions are changed to decimals, there would be a remainder of 0 in the division process.
Thousands place: the position just to the left of the hundreds place. For example, in the number 2,496, the 2 is in the thousands place. The 2 has a value of 2 thousands, or 2,000.
Thousandths place: the position in a decimal number just to the right of the hundredths place or the third place to the right of the decimal point. For example, in the decimal number 0.009, the 9 is in the thousandths place. The digit 9 has a value of 9 thousandths.
Three-digit number: a number that is written using three numerals. Some examples of three-digit numbers are 325, 100, and 726.
Two-digit number: a number that is written using two numerals. Some examples of two-digit numbers are 35, 27, and 99.
Whole Numbers : the set of numbers that includes zero and all counting numbers. For example 0,1, 2, 3, 4, 5, 6 are whole numbers. In a decimal the whole numbers are to the left of the decimal point.