What is a common item that can be used to teach skip counting by 20s?

Using all of the mentioned items—socks, shoes, and feet—provides a practical and engaging way to teach skip counting by 20s.

Socks and shoes can be combined in pairs, making it easy to visualize and practice counting in increments of 20 by grouping pairs together. For instance, if you have 10 pairs of shoes, you can quickly calculate that there are 20 shoes. This hands-on approach helps learners grasp the concept of skip counting as they physically manipulate the items.

Feet can also be introduced, as each person typically has two feet, leading to counting by 20 when considering groups of 10 people. This method incorporates real-world concepts and allows students to relate mathematical concepts to their daily lives.

Overall, using all of these items caters to different learning styles, whether visual, kinesthetic, or auditory, making the concept of skip counting more accessible and interesting for students.