The purpose of this task is to help students develop flexible strategies for adding and subtracting within 20. Students will pick 5 number cards from pre-made cards labeled 1-10. Then, another student will pick a "target number" between...

Using base-ten materials and place-value skills, 2nd graders gain a better understanding of how to add and subtract numbers.

Practice subtracting 1, 10, or 100 from a number. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.

Practice making groups of 10 and 100 while adding 3-digit numbers. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.

Practice adding numbers to make 5. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.

Practice adding by "putting together" (with numbers less than 10). Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.

The purpose of this task is for students to add, subtract, multiply, and divide decimal numbers in a real-world context. The weekly income earned by each person in the task is the median weekly income for their education level, but they...