Activity
University of Cambridge

University of Cambridge: Nrich: 1, 2, 3, 4, 5

For Students 3rd - 5th Standards
On this one page website sharpen your logic and problem solving skills while working on this challenge. The solution is available to double check your solution.
Activity
University of Cambridge

University of Cambridge: Nrich: A Magical Number Maze!

For Students 3rd - 5th
On this one page website sharpen your logic and problem solving skills while working on this challenge. The solution is available to double check your solution.
Activity
University of Cambridge

University of Cambridge: Nrich: Reverse Trick

For Students 3rd - 8th Standards
Get your calculator and your problem solving skills out to solve this challenge. You can find the solution right at this one page website.
Unit Plan
Khan Academy

Khan Academy: Add and Subtract on a Number Line

For Students 1st - 3rd Standards
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.
Professional Doc
Queen's Printer for Ontario

E workshop.on.ca: Number Sense and Numeration, Grds 4 6: Addition, Subtract [Pdf]

For Teachers 3rd - 8th Standards
Volume 2 of an eworkshop Guide to Effective Instruction in Math outlines and illustrates instructional strategies for teaching addition and subtraction to students in grades 4 through 6. Include a series of suggested activities.
Lesson Plan
Alabama Learning Exchange

Alex: Estimation Station

For Teachers 3rd - 5th Standards
During this lesson, students will learn the difference between estimation and guessing. Knowing how to estimate is an essential skill that will help students determine approximate totals as well as check the reasonableness of their...
Unit Plan
Khan Academy

Khan Academy: Adding Two Digit Numbers by Making Tens

For Students 1st - 3rd Standards
In this exercise, students practice adding two-digit numbers by making tens. Students receive immediate feedback and have the opportunity to get hints and try questions repeatedly.
Unit Plan
Khan Academy

Khan Academy: Adding Two Digit Numbers by Making Tens 2

For Students 1st - 3rd Standards
In this exercise, students practice adding two-digit numbers by making tens. Students receive immediate feedback and have the opportunity to watch tutorial videos, get hints, and try questions repeatedly.