Expressions
An expression in math is a combination of numbers, symbols, and operators (such as +, -, *, /) that represents a value. It can also include variables, which are placeholders for unknown values.
Examples of Expressions
Here are some examples of expressions:
- 3 + 5
- 2 * 4 - 7
- x + 10
- 4y - 2z
Evaluating Expressions
To evaluate an expression means to find its value by performing the operations and substituting the variables with given values. For example, to evaluate the expression 2 * 4 - 7, you would first perform the multiplication (2 * 4 = 8) and then the subtraction (8 - 7 = 1), resulting in a value of 1.
Importance of Expressions
Expressions are important in math because they allow us to represent and work with mathematical relationships and solve problems. They are fundamental to understanding algebra and other areas of mathematics.
.◂Math Worksheets and Study Guides Third Grade. Determine Appropriate Standard of Units
Study Guide
Determine Appropriate Standard of Units 
Worksheet/Answer key
Determine Appropriate Standard of Units Worksheet/Answer key
Determine Appropriate Standard of Units Worksheet/Answer key
Determine Appropriate Standard of Units
Worksheet/Answer keyWorksheet/Answer keyWorksheet/Answer keyThe resources above cover the following skills:
Measurement (NCTM)
Understand measurable attributes of objects and the units, systems, and processes of measurement.
Understand such attributes as length, area, weight, volume, and size of angle and select the appropriate type of unit for measuring each attribute.
Understand the need for measuring with standard units and become familiar with standard units in the customary and metric systems.
Understand that measurements are approximations and how differences in units affect precision.
Apply appropriate techniques, tools, and formulas to determine measurements.
Select and apply appropriate standard units and tools to measure length, area, volume, weight, time, temperature, and the size of angles.
Connections to the Grade 3 Focal Points (NCTM)
Measurement: Students in grade 3 strengthen their understanding of fractions as they confront problems in linear measurement that call for more precision than the whole unit allowed them in their work in grade 2. They develop their facility in measuring with fractional parts of linear units. Students develop measurement concepts and skills through experiences in analyzing attributes and properties of two-dimensional objects. They form an understanding of perimeter as a measurable attribute and select appropriate units, strategies, and tools to solve problems involving perimeter.