This task is intended for instruction, providing the students with a chance to experiment with physical models of triangles, gaining spatial intuition by executing reflections.

This short video and interactive assessment activity is designed to teach third graders about listing all factors.

This short video and interactive assessment activity is designed to teach fourth graders about listing common multiples.

This is a challenging fraction comparison problem. The fractions for this task have been carefully chosen to encourage and reward different methods of comparison.

In this number line task students must treat the interval from 0 to 1 as a whole, partition the whole into the appropriate number of equal sized parts, and then locate the fraction(s).

This short video and interactive assessment activity is designed to teach fifth graders about multiple rounds of division - long division word problems.

This short video and interactive assessment activity is designed to teach fifth graders about dividing 3 and 4 digit numbers by 2 digit numbers.

This short video and interactive assessment activity is designed to teach fourth graders about dividing 3 and 4 digit numbers by 2 digit numbers.

In this activity students compare objects to see which is longer and heavier than the other.

In this task students figure out how to draw the longest line on a map of the United States without hitting a border. They use color and line plots to keep track of their results.

The purpose of this task is for students to compare two options for a prize where the value of one is given $2 at a time, giving them an opportunity to "work with equal groups of objects to gain foundations for multiplication." This context also provides students with an introduction to the concept of delayed gratification, or resisting an immediate reward and waiting for a later reward, while working with money.

The purpose of this task is for students to find different pairs of numbers that sum to 9.

This instructional task gives students a hands-on experience with composing and decomposing geometric figures.

This task is for students who know how to use base 10 blocks.

This task is a straightforward task related to adding fractions with the same denominator. The main purpose is to emphasize that there are many ways to decompose a fraction as a sum of fractions, similar to decompositions of whole numbers that students should have seen in earlier grades.

This tasks lends itself very well to multiple solution methods. Students may learn a lot by comparing different methods. Students who are already comfortable with fraction multiplication can go straight to the numeric solutions given below. Students who are still unsure of the meanings of these operations can draw pictures or diagrams.

The purpose of this instructional task is to motivate a discussion about adding fractions and the meaning of the common denominator. The different parts of the task have students moving back and forth between the abstract representation of the fractions and the meaning of the fractions in the context.

This task requires students to study the make-a-ten strategy that they should already know and use intuitively. In this strategy, knowledge of which sums make a ten, together with some of the properties of addition and subtraction, are used to evaluate sums which are larger than 10.

This task is to introduce students to the concept of reading an analog clock.