C

calculator

A tool that can help with mathematics. It can be used to check calculations and to see if answers to problems are reasonable.

capacity

1. The volume of the inside of a container.
2. The largest amount a container can hold.

certain

If something is certain, you know it will definitely happen.

circle

A two-dimensional (2-D) shape that is curved. Every point of the curve is the same distance from the center.

column

Figures or numbers arranged one above the other. Columns go up and down, or vertically.

combinations

Ways of putting things together in different orders.

common

Something that happens, or is found, often. For example, yellow is the most common color and red and green are the least common colors in the graph.

commutative property of addition

Changing the order of addends does not change the sum. For example, 3 + 5 = 5 + 3. (See also turn-around fact and turn-around rule.)

compare

To show or tell how two things are similar or different from each other. You often compare amounts or numbers to find which is smaller or larger. (See also greater than and less than.)

corner

The place where the sides of a 2-dimensional (2-D) shape or the edges of a 3-dimensional (3-D) shape meet to form an angle.

counting all strategy

An addition strategy in which you start at zero and count all the numbers until you reach the total.

counting back strategy

A subtraction strategy in which you start from the larger number and count back the smaller number to find the difference. For example, for 9 − 2, begin with 9 and count back 2: 8, 7.

counting on strategy

An addition strategy in which you start with one addend and count forward the amount of the second addend to find the total. For example, for 6 + 4, begin with 6 and count four more, 7, 8, 9, 10.

counting up strategy

A subtraction strategy in which you start from the smaller number and count how many numbers to the larger one. For example, to find 8 − 5, the student counts 6, 7, 8, which is 3 more.

cube

A three-dimensional (3-D) shape with six square faces that are equal in size.

cubic units

A cube-shaped unit used to measure volume. For example, if a cube measures 1 cm along each edge the cubic unit is cubic centimeter.

curved

Rounded; having a shape that bends smoothly.

cylinder

A three-dimensional (3-D) shape that has two matching circles on the ends and one curved side. A cylinder will slide or roll.