The number line is a useful tool when ordering positive and negative rational numbers.

This lesson helps build a strong culture of problem solvers, and it can work as an introduction in 1st grade or as a Kindergarten lesson!

Adding and subtracting numbers on a number line is a neat way to see how numbers are added and subtracted using visual interpretations.

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

A number of different ways to approach complex numbers and operations with them.

Given a set of numbers, learn how to tell which are rational and which are irrational. [2:17]

Khan Academy learning modules include a Community space where users can ask questions and seek help from community members. Educators should consult with their Technology administrators to determine the use of Khan Academy learning modules in their classroom. Please review materials from external sites before sharing with students.

En "Barbaroja, el Pirata", Tucker pierde su querido Lil' Squeakie luego de que sus amigos pasaran el dia enterrando tesoros en la arena. Clifford y Emily Elizabeth hacen su mision el encontrar el juguete tesoro de Tucker antes de la hora de dormir pero es mas dificil de encontrar de lo que ellos se imaginaron. Pero los piratas jamas se dan por vencidos! Ellos se imaginaron sus propios juguetes especiales para dormir y continuaron su mision hasta que desenterraron un seguro- pero muy arenoso- Lil' Squeakie!

The purpose of this task is to help students understand the connection between counting and cardinality. Thus, oral counting and recording the number in digit form are the most important aspects of this activity. However, teachers can extend this by making a bar graph about how many students are wearing the color each day.

This sample chapter from Hurst's book Picturing Math is an excellent resource for using picture books and activities for learning computation.

Find out how to solve a word problem by constructing a numerical expression. [1:21]

Khan Academy learning modules include a Community space where users can ask questions and seek help from community members. Educators should consult with their Technology administrators to determine the use of Khan Academy learning modules in their classroom. Please review materials from external sites before sharing with students.

This lesson [3:07] demonstrates conversion from written or spoken words to numbers and symbols. It is 9 of 9 in the series titled "Converting Words to Math."

This task gives students another way to practice counting and gain fluency with connecting a written number with the act of counting. This task should be introduced by the teacher and would then be a good independent center.

The most engaging way to practice counting with students is to have them count meaningful things in their lives. Since five-year-olds are very focused on themselves this is easily done by allowing them to count themselves, their friends and objects within the classroom that relate to their daily lives.

The objective of this lesson is to gain automaticity counting to 100 and to establish the importance of multiples of ten. The final goal of this lesson is for students to be able to count by tens and articulate the term for this.

Casual and clear but definitely upper-level discussion of rational, real, imaginary, and several other types of numbers. Links to related sites.