# Kindergarten Computation and Algebraic Thinking Resources

Enter two addends, then click next. The addends will show up as counters. Keep clicking next to see the commutative property in action.

A missing addend activity. There are ___ dots in a box. Some are red and some are blue. If you know how many blue dots there are, can you figure out how many red dots there should be?

This activity is meant to develop flexible, creative thinking about numbers and operations. Your goal is to move a from a starting number to a target number, but there are many ways to do this! Adjust the sliders to control the bounds of the numbers involved.

How many dots are there? How do you see it? This number talk resource is designed to give students lots of different ways of seeing and describing a number of dots, but with the added advantage of seeing the dots move from one arrangement to another. Use this with the goal of students flexibly describing many ways of composing/decomposing a number.

Explore ideas around equality, decomposition, missing addends, and more! Up the ante by finding the mystery number.

Adjust the slider to control the size of the numbers. One of the pieces (a part or the whole) is randomly provided. Use estimation to fill in the rest. Feedback provided.

Designed to develop ability to estimate reasonable answers in subtraction situations. Specify your own subtraction problem (or generate a random one), then represent the relative size of the subtrahend by shading a rectangle representing the minuend. Feedback on accuracy of shading is provided. (Not included but recommended: finish by estimate the size of the difference before actually doing the subtraction.)