How do I explain "make a 10" to my 2nd grade son for his math homework?

He could count his 10 fingers.

He could count out 10 Cheerios or M&Ms.

He could count his toes on one foot and add it to the number of toes on the other foot.

He could add:
5 + 5
6 + 4
7 + 3
8 + 2
9 + 1

i have no idea

To explain the concept of "making a 10" to your 2nd-grade son, you can use a visual and interactive approach. Here's a step-by-step explanation:

1. Start with a set of two-digit addition problems where one of the numbers is not a multiple of 10. For example, let's take the problem 7 + 8.
2. Draw two ten frames on a piece of paper or use manipulatives like counting blocks. A ten frame is a grid with two rows, each containing five cells.
3. Explain to your son that each cell in the ten frame can hold one object, like a block or counter. In total, the ten frame can hold ten objects.
4. Place 7 objects in the first ten frame. Count the objects together, emphasizing that there are seven.
5. Now, explain that we want to "make a 10" by adding 8 to the existing 7. Help your son understand that we need to fill the first ten frame completely and then move the remaining objects to the second ten frame.
6. Since the first ten frame is already filled with 7 objects, ask your son to add 3 more objects to complete it. Count together as he adds the 3 objects.
7. Once the first ten frame is filled, explain that we now have a total of 10 objects. Help your son count from the number 10 to reinforce the concept.
8. The remaining 5 objects can be placed in the second ten frame. Explain that we don't need to count them again because we already counted them when filling the first ten frame.
9. Finally, explain that the answer to 7 + 8 is 10 + 5, which equals 15.
10. Repeat this process with a few more examples to ensure your son grasps the concept of making a 10 to simplify addition problems.

By using visual aids like ten frames and providing hands-on practice, your son will gain a better understanding of making a 10 and how it relates to addition.