In this 8-lesson unit students use buttons to explore logical and numerical relationships that form the conceptual basis for understanding addition and subtraction operations. Topics include counting, ordinal numbers (and relative position), classification (attributes), relationships between numbers, addition of sets, commutativity of addition, sums to 10, fact families (including subtraction), three models of subtraction ("take away", comparative, missing addend), and bar graphs. Includes student activity sheets and a link to an online graphing applet.

In this 8-lesson unit students use buttons to explore logical and numerical relationships that form the conceptual basis for understanding addition and subtraction operations. Topics include counting, ordinal numbers (and relative position), classification (attributes), relationships between numbers, addition of sets, commutativity of addition, sums to 10, fact families (including subtraction), three models of subtraction ("take away", comparative, missing addend), and bar graphs. Includes student activity sheets and a link to an online graphing applet.

In this Illuminations lesson plan students explore the use of variables as they solve for the weights of objects using information presented in pictures. Learners model situations that involve adding and subtracting whole numbers, using objects, pictures, and symbols. A student activity sheet is available and downloadable (pdf).

This short video and interactive assessment activity is designed to teach second graders about challenging flow chart (numbers to 1,000).

This short video and interactive assessment activity is designed to teach third graders about challenging flow chart (numbers to 1,000).

This lesson develops number skills, understanding of coin values, and the concept of equivalence. Students use coin blocks, concrete representations of the value of coins (pennies, nickels, dimes, and quarters), to compose and decompose values up to a dollar. The resource includes a 3-minute video for teachers on how to build the coin blocks prior to the lesson. An interactive game, Coin Box, provides additional practice for students and is cataloged separately.

In this Flash game, students may use a variety of activities to practice counting, collecting, exchanging, and making change for coins. Coin representations may show their amounts or not; coins may also be represented by coin tiles on a 10x10 grid, to help visualize their values. The five activities are: count, in which students determine the value of a given set of coins; collect, in which students choose coins to represent a given value; exchange, in which students use the smallest number of coins to represent a given value; change from coins, in which students are given a set of coins and asked how much change would be for a dollar (essentially counting up); and change from value, in which students are given a price owed (from a dollar) and asked to make change. There is a "bank" at the lower left side of the applet in which coins may be exchanged for other coins of the same value.

In this 6-lesson unit, students explore 5 models of subtraction (counting, sets, number line, balanced equations, and inverse of addition) using connecting cubes. The lesson activities focus on the comparative mode of subtraction as children investigate the relationship between addition and subtraction, write story problems in which comparison is required, and practice the subtraction facts. The lessons include printable student activity sheets, a bibliography of children's counting books, questions for student discussion and teacher reflection, assessment options, extensions, and links to online applets (cataloged separately).

This short video and interactive assessment activity is designed to teach second graders about comparing with multi-step addition and subtraction - word problems.

This short video and interactive assessment activity is designed to teach second graders about comparing with one-step addition and subtraction - word problems.

This short video and interactive assessment activity is designed to teach second graders about comparing with two-step addition and subtraction.

This short video and interactive assessment activity is designed to teach second graders about comparing with two-step addition and subtraction - word problems.

This short video and interactive assessment activity is designed to teach first graders about completing the addition sentence (sums to 100).

This short video and interactive assessment activity is designed to teach second graders about completing the addition sentence (sums to 100).

This short video and interactive assessment activity is designed to teach second graders about completing the addition sentence (sums to 20).

This video and interactive assessment activity will help first grade students learn how to complete subtraction sentences.

This short video and interactive assessment activity is designed to teach second graders about completing the subtraction sentence (numbers up to 20).