# K.OA.A.4

For any number from 1 to 9, find the number that makes 10 when added to the given number, e.g., by using objects or drawings, and record the answer with a drawing or equation.

## Summary:

This standard asks students to determine what number can be added to a given number to make 10. Objects such as counters, blocks, fingers, and other manipulatives can be be used and then drawn on paper to represent this problem. Students who have mastered this skill can "make ten" as a strategy for adding; for example, to add 8 + 6, they can decompose the 6 into 2 + 4 (note that this also uses skills from K.OA.3), knowing that 8 + 2 makes ten. Then they can observe that 8 + 2 + 4 = 10 + 4 = 14.

## Understanding the Standard:

• Fact families are especially beneficial in helping students to understand the relationship between addition and subtraction. Being able to subtract from 10 might give students an advantage when determining what number can be added to a given number to make 10.
• Students should have ample opportunities to use manipulatives in constructing concrete models of missing-addend problems.
• Drawings can be used to further develop understanding the processes involved in finding the difference in a subtraction problem.
• The use of manipulatives and technologies is helpful for those students needing additional visual cues and hands-on experiences. Using a set of ten objects and decomposing it to make two smaller sets will help children visualize what they are learning.
• Starting with a random number less than 10, use the word "addition" to represent an example that includes the number 10 and a variable in the form of  "?", e.g., 2 + ? = 10.

## Questions to Focus Instruction:

• When given the first addend, can students correctly solve simple addition facts in which the sum is 10 ?
• Are students able to take a drawing of a given mathematical situation that makes ten and write it in equation form?
• Are students able to represent their method of problem-solving with manipulatives or drawings using 10 objects?

## Skills

Prior to: Students have an understanding that two sets can combine to form a single set with a greater number of objects. Studnets should understand that the operation of addition gives the number of objects in the combined set.