S

sample

Some of the items from a whole group.

second

A unit for measuring time. There are 60 seconds in a minute.

separate (take away)

A type of subtraction problem where part of the whole is separated or taken away from the whole. For example, I had 8 bananas and gave 4 to my sister. How many do I have now?

side

One of the lines forming the outline of a shape. For example, a square has four sides.

skip count

Count forward or backward by a number greater than one. For example: 2, 4, 6, 8 is skip counting by twos.

solution

The answer to a problem.

sphere

A three-dimensional (3-D) shape shaped like a ball.

square

A two-dimensional (2-D) shape with four equal sides and four square corners.

square corner

You can fit a square in a square corner. The corner of a sheet of paper is a square corner.

square inch

The area of a square with a side length of one inch.

square units

Units of measure that are square that are used to measure area.

strategy

A way of solving a problem. For example, counting back and using doubles are strategies for math facts.

subtract zero rule

A rule that says when you take zero from a number, the number stays the same. For example, 3 − 0 = 3.

subtraction

Taking one amount away from another. For example, 5 − 3 = 2. The symbol to show subtraction is −.

sum

The answer to an addition problem.

symmetry

A shape has symmetry if it is made up of parts that are the same shape and size. For example, if you fold a shape in half, and the two sides line up perfectly, the shape has symmetry. (See also line of symmetry and line symmetry.)