CK-12 Foundation
Ck 12: Elem Math: Adding and Subtracting Missing Number
[Free Registration/Login may be required to access all resource tools.] The resource is a video showing students how to find a missing number in a multi-step addition and subtraction problem using inverse operations. Adaptive practice...
Primary Resources
Primary Resources: Basic Addition and Subtraction
An extensive collection of teacher resources to help in teaching and reviewing the concepts of basic addition and subtraction. There are many worksheets, activities, PowerPoint presentations, smartboard activities, Word, Excel, and pdf...
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: 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.
Khan Academy
Khan Academy: Addition & Subtraction: Find the Missing Value
Practice finding the missing value in an addition or subtraction equation involving negative numbers.
CK-12 Foundation
Ck 12: Elem Math: Completing the Addition Sentence Sums to 20
[Free Registration/Login may be required to access all resource tools.] The video shows how to count backwards to determine the missing number in an addition problem. The video is followed by practice problems to assess student...
CK-12 Foundation
Ck 12: Elem Math: Adding and Subtracting With Parentheses
[Free Registration/Login may be required to access all resource tools.] The resource includes a video tutorial on how to find a missing number in a multi-operational problem by working backwards. The video is followed by practice...
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.