Primary Resources
Primary Resources: Addition and Subtraction Higher Numbers
An extensive selection of teacher resources to aide in teaching and reviewing addition and subtraction of two and three digit numbers, inverse operations, counting on, and other mental strategies for addition and subtraction. Resources...
US Department of Education
Helping Your Child Learn Math: Math on the Go
Parents and children explore math in the world around them in this collection of math activities. Simple, engaging, and fun, these lessons offer learners the opportunity to discover math even when they're "on the go." An excellent...
AAA Math
Aaa Math: Estimation
Improve your estimation and rounding skills with these interactive games that are challenging and fun. Excellent skills practice for rounding, estimating sums and differences, and front-end estimation. Links to lesson plans, teacher...
Other
Casting Out Nines: A Math Computation Checking Strategy
It's a mathematician's dream come true. An easy trick for checking mathematical computations, without a calculator! Believe it or not, it works with all four operations.
Queen's Printer for Ontario
E workshop.on.ca: Effective Instr'n in Math, K 6: Multidigit Computation [Pdf]
Volume 5 in an eworkshop Guide to Effective Instruction in Math outlines and illustrates instructional strategies for teach basic facts and multidigit computation to students in kindergarten through grade 6.
Teaching Treasures Publications
Teaching Treasures: Year Four Timed Mental Math (Page 2)
Improve your computations skills in all four operations with this timed interactive worksheet. Solve ten problems in five minutes or less. Problems are presented in horizontal format and answers can be checked immediately. This worksheet...
Teaching Treasures Publications
Teaching Treasures: Year One Timed Mental Math (Page 3)
Try to solve ten addition or subtraction problems in less than five minutes using this interactive worksheet. Immediate feedback is given. A suitable tool for use as a quick assessment.
Teaching Treasures Publications
Teaching Treasures: Year One Timed Mental Math (Page1)
Test your computation skills using this timed interactive worksheet. Five minutes is the time limit. Answers can be checked when finished. This short activity would be suitable for a quick assessment.
Teaching Treasures Publications
Teaching Treasures: Year Six Timed Mental Math (Page 2)
Improve your computations skills in all four operations with this timed interactive worksheet. Solve ten problems in five minutes or less. Problems are presented in horizontal format and answers can be checked immediately. This worksheet...
Other
Curious math.com: Math Is an Attitude
This site offers numbers tricks to help multiply and divide large numbers mentally. There are also tricks for powers and roots of numbers.
Texas Instruments
Texas Instruments: Mad Minutes
This activity should help kids to perform quick computations using mental math, become less reliant on calculators for computation, and remember algorithms for common math problems by using repetition and practice.