**Why does "of" mean multiply?**

- Dr. Math explains why "of" indicates multiplication. Click "Dr. Math Home" or scroll to the bottom to search for answers to your own "why" questions.

**SEDL's Common Core State Standards Video Series - 4.NF.1**

- This video for standard 4.NF.1 depicts the essence of the standard using clear mathematical symbols and three different visual models. This is one in a larger series of mathematics and ELA standard videos.

**Problems of the Month**

- Inside Mathematics' Problems of the Month are designed to be used at multiple levels to promote a problem-solving theme. The problem is divided into five levels, Level A through Level E, to allow access and scaffolding for the students into different aspects of the problem and to stretch students to go deeper into mathematical complexity.

**Against "Answer-Getting"**

- Phil Daro goes into detail on the problems of "answer-getting," illustrating one of the key shifts of the College and Career Readiness Standards.

**My Favorite No**

- Leah Alcala gives her students a warm-up problem at the beginning of every class, which they solve on index cards. She quickly sorts through them, and from the wrong answers chooses her "favorite no." She and her students then analyze what's right about the solution before delving in to what the writer doesn't understand that led them to answer incorrectly.

**Illustrative Mathematics' Fractions Progression**

- In a series of short videos, Introduction through Unit 7, you can watch an overview of the meaning of fractions standards. Don't miss the valuable links to "Illustrations" in each unit under the video. Here you'll find lots of quick activities and problems (not worksheets) to try with your students.