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...
AAA Math
Aaa Math: Addition Using Estimation
This site explains how to estimate sums by rounding whole numbers. Games and exercises are provided to practice the skill.
E-learning for Kids
E Learning for Kids: Math: Inca Temple: Three Digit Numbers
On this interactive website students practice various math skills using a real life scenario in a classroom. Those skills include identifying three-digit numbers, putting numbers in ascending and descending order, and rounding numbers to...
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...
Mr. Martini's Classroom
Mr. Martini's Classroom: Equivalent Addition Problems: Fill in the Blank
Students choose the correct number to balance the addition equation and create an equivalent sum.
Mr. Martini's Classroom
Mr. Martini's Classroom: Addition Cards, Fill in the Blank
Students fill in the blank with the correct number to solve the addition problems. The problem changes color when the correct number is typed.
Beacon Learning Center
Beacon Learning Center: Circus Fun
Students can practice adding up to three whole numbers with regrouping in this interactive web lesson.