CK-12 Foundation
Ck 12: Elem Math: Adding, Subtracting, and Multiplying Missing Number
[Free Registration/Login may be required to access all resource tools.] A learning module where students must apply the order of operations to find the missing numbers in equations involving addition, subtraction, and multiplication. A...
Khan Academy
Khan Academy: Find Missing Divisors and Dividends (1 Digit Division)
Find missing divisors and dividends in 1-digit division problems. Quotients are less than or equal to 10. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video tutorial, or receive hints....
Khan Academy
Khan Academy: Addition & Subtraction: Find the Missing Value
Practice finding the missing value in an addition or subtraction equation involving negative numbers.
Khan Academy
Khan Academy: Addition & Subtraction: Find the Missing Value
Practice finding the missing value in an addition or subtraction equation involving negative numbers. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
National Council of Teachers of Mathematics
Nctm: Figure This: Which Is Worth More, a Smile or a Frown?
Solve for the value of the smiles and frowns to find out how much a smile is worth, in this activity. A challenge that focuses on number sense, number combinations, and unknowns. Included are examples of how this skill is applied in real...
CK-12 Foundation
Ck 12: Elem Math: Add and Subtract to 100 Mixed Operations and Word Problems
[Free Registration/Login may be required to access all resource tools.] This is a set of practice problems where students solve addition and subtraction problems in order to determine missing numbers to keep the equation balanced. When...
Oswego City School District
Regents Exam Prep Center: Truth Value of Open Sentences
What happens when there is not enough information to solve a problem? Find out at this test prep site, how missing information or "open sentences" can change the value or truth of a math equation. Practice understanding and applying this...