EngageNY
The Relationship of Division and Subtraction
See how division and subtraction go hand-in-hand. The fourth installment of a 36-part module has scholars investigate the relationship between subtraction and division. They learn using tape diagrams to see that they can use repeated...
Illustrative Mathematics
Sugar in Six Cans of Soda
Understanding how to multiply a whole number by a fraction is the key concept. Young mathematicians create a visual model of this real-world example and find the solution. Extensions are possible for making this an even richer activity....
Inside Mathematics
Number Towers
Number towers use addition or multiplication to ensure each level is equal. While this is common in factoring, it is often not used with algebraic equations. Solving these six questions relies on problem solving skills and being able to...
Inside Mathematics
Magic Squares
Prompt scholars to complete a magic square using only variables. Then they can attempt to solve a numerical magic square using algebra.
Khan Academy
Khan Academy: Adding Decimals: Thousandths
In this exercise, students practice adding decimals in the thousandths place. Students receive immediate feedback and have the opportunity to get hints and try questions repeatedly.