Baffled by the math homework your child is bringing home? Here’s a cheat sheet to help you save face while fielding her questions. If these terms and explanations don’t bring it all back, read our article about what your child is learning in math this year: see math & science grade 1 learning milestones and grade 2 learning milestones. It also wouldn’t hurt to chat with her teacher if you think your child needs extra help that you can’t provide.

**Associative property of addition**

Changing the groupings in an addition problem won’t change the answer. For example: (a + b) + c = a + (b + c), or (1 + 2) + 4 = 1 + (2+4) = 7

**Circle**

A set of points in a flat plane that are all the same distance from a fixed center point.

**Commutative property of addition**

Changing the order of numbers in an addition problem won’t change the answer. For example: a + b = b + a, or 8 + 5 = 5 + 8 = 13

**Cone**

A three-dimensional figure that rises from a circular base to a peak.

**Cube**

A three-dimensional figure with six square faces.

**Cylinder**

A three-dimensional figure whose two parallel bases are identical circles.

**Data**

Measurements or other numerical information.

**Decimal number**

A number with one or more places to the right of a decimal point.

**Difference**

The result of subtracting two numbers.

**Digit**

The symbols 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9. The number 123 has three digits: 1, 2, and 3.

**Even number**

A number with 0, 2, 4, 6, or 8 in the ones place.

**Face**

A flat surface on a three-dimensional figure like a cube or pyramid.

**Fraction**

A number that represents a portion or whole. In the fraction 3/4, 3 is the numerator and 4 is the denominator, so the number indicates 3 parts out of a total of 4.

**Graph**

A drawing that illustrates data.

**Inequality**

An expression that shows that two amounts are not equal, like 4 ≠ 3.

**Mode**

The most frequent number in a set of terms. In the set of numbers 1, 4, 5, 7, 7, 9, the mode is 7.

**Odd number**

A number with 1, 3, 5, 7, or 9 in the ones place.

**Pyramid**

A three-dimensional figure with a polygon (a shape with straight lines, like a square or a triangle) for a base, and triangular faces that create a peak.

**Range**

The difference between the smallest and biggest numbers in a group.

**Rectangle**

A shape with four sides and four 90-degree angles. (A square is a type of rectangle with four equal sides.)

**Sphere**

A ball; a three-dimensional circle, whose points are all the same distance from a fixed center point.

**Square**

A shape with four equal sides and four 90-degree angles. (A square is a specific type of rectangle.)

**Triangle**

A shape with three straight sides.

**Vertex**

The peak opposite the base of a figure.

**Whole numbers**

The “counting” numbers, including zero (0, 1, 2, 3, 4, 5, 6, etc.). Decimal numbers and fractions are not included in this set.