This resource from the National Library of Virtual Manipulatives shows students how to rename fractions to have a common denominator and then add them. It is appealing because it visually engages the students by showing them what happens to a unit (a rectangle is used here) as the denominator increases or decreases. As the denominator increases or decreases, the partitions are shown accordingly, and the effect on the numerator is shown as well. This is a convenient, visual way to show students how to manipulate fractions for adding.

Kahn Academy video - How to add and subtract fractions with like and unlike denominators.

Remember your multiplication tables? ... me neither. Brush up on your multiplication, division, and factoring skills with this exciting game. No calculators allowed! The students will be given mutiplication and division problems which they must answer. They also have the option of being given a number then stating the factors of how that number was attained using either multiplication or division.

This activity is designed to determine the appropriate instructional level for a student in a one-on-one interaction with the teacher.

Full course of Algebra 1 is presented online by Georgia Virtual Learning. Audio, video, text, games and activities are included to engage ninth grade students in learning.

Overview of how the Pennsylvania Common Core Standards for Mathematics are driving changes in classrooms and schools, and where resources can be found to support the implementation of those changes.

This task suggests methods of introducing and continuing choral counting in the classroom.

The purpose of this task is to assess studentsŐ understanding of multiplicative and additive reasoning.

This task requires students to think of dimes and pennies as fractions of dollars.

Khan Academy video tutorial. Solving one and two step equations-this is made slightly more difficult than the Simple Equations tutorial by adding constants to the variable term.

This lesson unit is intended to help you assess how well students are able to: solve simple problems involving ratio and direct proportion; choose an appropriate sampling method; and collect discrete data and record them using a frequency table.

Khan Academy tutorial video that uses Excel spreadsheet and actual income data to predict annual income and expresses why lines and models are useful and interesting.

In Module 1, students’ understanding of the patterns in the base ten system are extended from Grade 4’s work with place value of multi-digit whole numbers and decimals to hundredths to the thousandths place. In Grade 5, students deepen their knowledge through a more generalized understanding of the relationships between and among adjacent places on the place value chart, e.g., 1 tenth times any digit on the place value chart moves it one place value to the right. Toward the module’s end students apply these new understandings as they reason about and perform decimal operations through the hundredths place.

Find the rest of the EngageNY Mathematics resources at https://archive.org/details/engageny-mathematics.

This learning video addresses a particular problem of selection bias, a statistical bias in which there is an error in choosing the individuals or groups to make broader inferences. Rather than delve into this broad topic via formal statistics, we investigate how it may appear in our everyday lives, sometimes distorting our perceptions of people, places and events, unless we are careful. When people are picked at random from two groups of different sizes, most of those selected usually come from the bigger group. That means we will hear more about the experience of the bigger group than that of the smaller one. This isn't always a bad thing, but it isn't always a good thing either. Because big groups ''speak louder,'' we have to be careful when we write mathematical formulas about what happened in the two groups. We think about this issue in this video, with examples that involve theaters, buses, and lemons. The prerequisite for this video lesson is a familiarity with algebra. It will take about one hour to complete, and the only materials needed are a blackboard and chalk.

The purpose of the task is for students to solve a multi-step multiplication problem in a context that involves area. In addition, the numbers were chosen to determine if students have a common misconception related to multiplication.

Khan Academy video Apply and extend previous understanding of multiplication and division and of fractions to multiply and divide rational numbers

(Nota: Esta es una traducción de un recurso educativo abierto creado por el Departamento de Educación del Estado de Nueva York (NYSED) como parte del proyecto "EngageNY" en 2013. Aunque el recurso real fue traducido por personas, la siguiente descripción se tradujo del inglés original usando Google Translate para ayudar a los usuarios potenciales a decidir si se adapta a sus necesidades y puede contener errores gramaticales o lingüísticos. La descripción original en inglés también se proporciona a continuación.)

En el módulo 1, la comprensión de los estudiantes de los patrones en el sistema Base Ten se extiende desde el trabajo de Grado 4 con el valor de lugar de números enteros y decimales de varios dígitos a centésimas hasta el lugar de milésimas. En el grado 5, los estudiantes profundizan su conocimiento a través de una comprensión más generalizada de las relaciones entre y entre los lugares adyacentes en la tabla de valor del lugar, por ejemplo, 1 décimo veces cualquier dígito en la tabla de valor del lugar lo mueve un valor de un lugar a la derecha. Hacia el final del módulo, los estudiantes aplican estos nuevos entendimientos, ya que razonan y realizan operaciones decimales a través del lugar de las centésimas.

Encuentre el resto de los recursos matemáticos de Engageny en https://archive.org/details/engageny-mathematics.

English Description:
In Module 1, students’ understanding of the patterns in the base ten system are extended from Grade 4’s work with place value of multi-digit whole numbers and decimals to hundredths to the thousandths place. In Grade 5, students deepen their knowledge through a more generalized understanding of the relationships between and among adjacent places on the place value chart, e.g., 1 tenth times any digit on the place value chart moves it one place value to the right. Toward the module’s end students apply these new understandings as they reason about and perform decimal operations through the hundredths place.

Find the rest of the EngageNY Mathematics resources at https://archive.org/details/engageny-mathematics.

This interactive Flash animation allows students to explore size estimation in one, two and three dimensions. Multiple levels of difficulty allow for progressive skill improvement. In the simplest level, users estimate the number of small line segments that can fit into a larger line segment. Intermediate and advanced levels offer feature games that explore area of rectangles and circles, and volume of spheres and cubes. Related lesson plans and student guides are available for middle school and high school classroom instruction. Editor's Note: When the linear dimensions of an object change by some factor, its area and volume change disproportionately: area in proportion to the square of the factor and volume in proportion to its cube. This concept is the subject of entrenched misconception among many adults. This game-like simulation allows kids to use spatial reasoning, rather than formulas, to construct geometric sense of area and volume. This is part of a larger collection developed by the Physics Education Technology project (PhET).