This short video and interactive assessment activity is designed to teach second graders about adding or subtracting lengths in one step.

This short video and interactive assessment activity is designed to teach second graders about adding and subtracting (numbers up to 20) - word problems.

This short video and interactive assessment activity is designed to teach fourth graders about adding of compound units of length (english units).

This short video and interactive assessment activity is designed to teach fourth graders about adding and subtracting fractions - word problems.

This short video and interactive assessment activity is designed to teach fifth graders about adding and subtracting fractions with different denominators.

This short video and interactive assessment activity is designed to teach fourth graders about adding 3 numbers - word problems.

This short video and interactive assessment activity is designed to teach fourth graders about adding capacities in compound units (english units).

This short video and interactive assessment activity is designed to teach fourth graders about adding decimals - word problems.

This short video and interactive assessment activity is designed to teach fifth graders about adding fractions with different denominators.

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.

This short video and interactive assessment activity is designed to teach fifth graders about adding mixed numbers with common denominators.

This short video and interactive assessment activity is designed to teach fifth graders about adding, subtracting, multiplying and dividing.

This short video and interactive assessment activity is designed to teach fourth graders about adding, subtracting, multiplying and dividing.

This short video and interactive assessment activity is designed to teach fifth graders about adding, subtracting, multiplying, and dividing with parentheses.

This short video and interactive assessment activity is designed to teach fifth graders about adding, subtracting, and multiplying.

This short video and interactive assessment activity is designed to teach fourth graders about adding, subtracting, and multiplying with parentheses.

This short video and interactive assessment activity is designed to teach second graders about adding unit lengths in one step (english units).

This short video and interactive assessment activity is designed to teach fourth graders about adding unit lengths in one step (english units).