This explains the Order of Operations. It addresses the Common Core 5th Grade Math Operations and Algebraic Thinking stardard 5.OA.1: Use parentheses, brackets, or braces in numerical expressions, and evaluate expressions with these symbols.
Another site/link rec. from Dr. Nickie "Angles is a 4th Grade Standard in the CCSS. Here is a great set of activities to have students do in their math journals. I (Dr. Nickie) really like it because it is interactive, engaging and standards-based. Check it out!Types of Angles math journal @ Runde's Room."