Ask students what they think of when they hear the word "multiple". Some students may have heard the word before, such as "you have multiple siblings", and others may have no reference for the word.

Tell students we use the word "multiple" to describe numbers we can skip count by. For instance, 2, 4, 6, and 8 are all multiples of 2 because we call them out when counting by 2's.

Have students practice giving a multiple of numbers less than 10. For instance, ask students "what is a multiple of 3?". Allow multiple answers to help students recognize all numbers have many multiples.

Once students are comfortable, invite them to play a game. Each student will write down a multiple of a given number. Their multiple must be less than 50. The person with the biggest multiple that no one else has picked will gain a point.

For example, if working with 2's, the biggest multiple less than 50 is 48. If more than one student writes down 48, move onto 46, again if more than one student writes down 46, move to 44 and continue until you reach a multiple only one student wrote.

Play a few rounds with different values. This warm up can be reused at any time to encourage students to think about multiples. It also elicits thinking by counting down rather than counting up to build multi-directional fluency.