AAA Math
Aaa Math: Adding Two Digit Numbers Mentally
Read these two strategies for adding two-digit numbers in your head. Then try out the one you like better by playing the game. Running totals of your correct and incorrect answers as well as a percent score of your correct answers will...
Khan Academy
Khan Academy: Add and Subtract on a Number Line
Practice adding and subtracting numbers like 554 and 237 using a number line. All numbers are less than 1000. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
Khan Academy
Khan Academy: Estimate to Add and Subtract Multi Digit Whole Numbers
Use estimation to find a reasonable solution to multi-digit addition and subtraction problems. Numbers are less than or equal to 1000. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a...
Khan Academy
Khan Academy: Addition Using Groups of 10 and 100
In this exercise, students practice addition using groups of 10 and 100. Students receive immediate feedback and have the opportunity to get hints, watch a video tutorial, and try questions repeatedly. CCSS.Math.Content.3.NBT.A.2...