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....
CK-12 Foundation
Ck 12: Elem Math: Finding the Subtraction Sentence by Pattern Numbers Up to 20
[Free Registration/Login may be required to access all resource tools.] The video shows how to find a pattern in a series of subtraction problems to determine the missing problem in the set. The video is followed by additional problems...
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...
SMART Technologies
Smart: Colorful Painter Fact Families
Find the missing numbers in the fact family number sentences.
CK-12 Foundation
Ck 12: Elem Math: Selecting the Incorrect Subtraction Sentence Ii
[Free Registration/Login may be required to access all resource tools.] The video shows how to finding the missing number in a two-digit subtraction problem by working backwards. The video is followed by a series of practice questions to...
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...
Math Is Fun
Math Is Fun: Common Number Patterns
Developed by a mathematics teacher from the UK, this page identifies and illustrates several common number patterns.
Khan Academy
Khan Academy: Ratio Tables
Explains what ratio tables are. Includes simple examples and a few practice problems.
CK-12 Foundation
Ck 12: Arithmetic: Equivalent Ratios
[Free Registration/Login may be required to access all resource tools.] Learn what ratios are and how to arrive at equivalent ratios. Identify and write equivalent ratios.