2nd Grade Computation and Algebraic Thinking Resources
This is meant to develop understanding of addition and subtraction of 1 and 10. You are given a starting number and and ending number (the relationship between having been determined by the adjustable "Difficulty"). Your job is to get to the ending number by adding or subtracting one(s) or ten(s). Choose a representation to help your thinking and try to find the most efficient pathway.
What are the missing digits of this equation? Think strategically about the possibilities, then click the buttons to find out. Play this game slowly with lots of conversations about what you know/don't know. See this Marilyn Burns blog post for more information and instructional ideas.
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.
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.)
Designed to develop a specific strategy when faced with a regrouping problem in subtraction. Specify a subtraction problem, then see that represented on the number line as the distance between the two numbers. Since that is a fixed distance, explore how it can be found by adjusting the minuend and subtrahend to generate equivalent subtraction problems, some which would not require regrouping.