Khan Academy: Missing Numbers in Addition and Subtraction

Learners observe one factor and the sum and fill in the blank for the other missing factor. They solve 32 problems.

Whether your pupils need extra help or they simply need to practice their basic computation skills, this packet will do the trick. It includes a written rationale, answer key, and over 10 pages of double-digit addition and subtraction...

Reinforce addition and subtraction with a 30-problem arithmetic worksheet in which scholars add and subtract numbers between one through 10. 

Demonstrates how to find missing numbers in addition and subtraction equations within 100. [5:44]

Watch Sal find missing numbers between 0 and 120. Includes a video, transcript, and question and answer section. [1:53]

Understanding the inverse relationship between addition and subtraction is essential for developing fluency in young mathematicians. Zoe and RJ explain how three numbers can form fact families that make two addition and two subtraction...

Use number lines to find the missing value in multi-digit subtraction problems.

Practice working with whole numbers in written form. For example, "one thousand four hundred three" is the written form of 1403. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or...

Sal shows some techniques for doing mental addition, such as making groups of 10 and 100. Includes a video, transcript, and question and answer section. [7:27]

Sal solves for the missing number in problems like ___ + 261 = 630.