4-5

An acute angle is a small, sharp angle that measures less than 90 degrees, like the corner of a slice of pizza.

2-3

Objects arranged in equal rows and columns, showing multiplication as a rectangle of items.

K-1

Our number system built on groups of ten, where each place is worth ten times the place to its right.

4-5

A century is a period of 100 years, such as the 21st century from 2001 through 2100.

2-3

Order of numbers doesn't change the result of addition or multiplication, like 4+5 = 5+4.

K-1

Breaking a number or shape into smaller parts to understand its structure, like splitting 7 into 5 and 2.

2-3

Different fractions that name the same amount, like 1/2 and 2/4, shown by equal-sized parts of a whole.

4-5

The largest number that divides two or more numbers evenly, like 6 is the GCF of 12 and 18.

2-3

Horizontal means side to side or straight across, like the top edge of a table.

2-3

The third position from the right in a whole number, showing how many hundreds the number contains.

2-3

A fraction where the numerator is larger than the denominator, like 5/4, representing more than one whole.

2-3

An inch is a small unit of length used to measure objects, such as a pencil, with a ruler.

2-3

To explain your math thinking with reasons, evidence, or proof so others can follow your reasoning.

2-3

The part of a graph that explains what each symbol represents, like one picture equals two students.

2-3

Length is the measurement of how long something is, from one end to the other.

K-1

Less than means one number or amount is smaller than another, as in 3 < 8.

2-3

A graph that shows data using X marks above a number line, making it easy to see patterns.

2-3

A whole number combined with a proper fraction, like 2 1/3, showing an amount between whole numbers.

K-1

A straight line with numbers placed in order, showing values, distances, and relationships visually.

K-1

4-5

The rules for which math operations to do first, remembered by PEMDAS: Parentheses, Exponents, Multiplication/Division, Addition/Subtraction.

K-1

The value of a digit based on its position in a number, like the 5 in 50 means five tens.

4-5

A pyramid is a solid shape with one polygon base and triangular faces that meet at one point called the apex.

2-3

A quarter is one of four equal parts of a whole, written as 1/4, such as one slice of a pizza cut into four equal slices.

2-3

The answer to a division problem, showing how many times one number fits into another.

K-1

2-3

Trading ones for tens or tens for ones when adding or subtracting multi-digit numbers.

K-1

Counting by a number other than one, like 2, 5, or 10, to count faster and build multiplication readiness.

2-3

Standard form writes a number with digits, such as 406 for four hundred six.

2-3

A visual model using bars to show parts of a whole or compare quantities in word problems.

2-3

Seeing a group as one unit while knowing its value, like one ten-rod worth ten ones.

4-5

A letter that stands for an unknown number in an expression or equation, like x in x + 3 = 7.

2-3

A decade is a group of 10 years in a row, such as 2020 through 2029.

K-1

An ordinal number tells the position of something in order, like 1st, 2nd, or 3rd in a race.

2-3

Width is the distance across an object from one side to the other.

K-1

A math question written as a story or real-life situation that you solve using numbers and operations.

4-5

The horizontal number line on a coordinate grid, where x-coordinates show left-right position.

4-5

The vertical number line on a coordinate grid, where y-coordinates show up-down position.

K-1

The rule that adding zero doesn't change a number, and multiplying any number by zero gives zero.