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Math Bugs Me: Add Subtract Integers

For Students 6th - 8th Standards
This website provides students tips on how to add integers using absolute value and by introducing them to a pattern.
Website
National Council of Teachers of Mathematics

The Math Forum: Ask Dr. Math: Triangle Inequality

For Students 9th - 10th
Dr. Math gives a hint of how to prove the triangle inequality theorem when answering a question posed about proving an absolute value problem using the triangle inequality theorem.