CK-12 Foundation
Ck 12: Elem Math: Calculating Sums (Numbers Up to 100,000)
[Free Registration/Login may be required to access all resource tools.] In this learning module, students are presented with a set of numbers up to 100,000, most of which end with one or more zeroes, and must apply their understanding of...
CK-12 Foundation
Ck 12: Elem Math: Fact Families Numbers to 1000
[Free Registration/Login may be required to access all resource tools.] The video describes how to determine what number sentence is missing in the fact family.
SMART Technologies
Smart: Colorful Painter Fact Families
Find the missing numbers in the fact family number sentences.
CK-12 Foundation
Ck 12: Elem Math: Filling in the Missing or Sign Numbers to 100
[Free Registration/Login may be required to access all resource tools.] The video works through 2-digit addition and subtraction problems to determine which number sentence coincides with the given value. The video is followed by...
CK-12 Foundation
Ck 12: Elem Math: Filling in the Missing or Sign Numbers to 1000
[Free Registration/Login may be required to access all resource tools.] The video works through a 3-digit addition problem to determine if the correct operation for the number sentence is addition or subtraction. The video is followed by...
Math Slice
Math Slice: Math Crossword Slice Special Test
Use this interactive math crossword puzzle to build number sense skills. Simply fill in the missing numbers based on the operation. Immediate feedback given to responses.
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...
Lawrence Hall of Science
The Math Page: Skill in Arithmetic: The Meaning of Subtraction, and Mental Calculation
This website explains and defines basic subtraction. There are practice problems at the very end of this lesson.