Lesson objective: Understand that skip counting by fives and tens supports telling and writing time to the nearest five minutes. Applying the knowledge of counting by fives and tens to the clock equips students to be successful in the real-life situation of telling time. Skip counting by fives and tens also lays the foundation for mentally adding and subtracting numbers.

Students bring prior knowledge of counting by tens from (K.CC.A.1). This prior knowledge is extended to skip counting by fives as students investigate the numerical patterns created when counting by fives and tens. A conceptual challenge students may encounter is understanding when we skip count, we are adding five or ten each time. This results in a numerical pattern in our base ten system.

The concept is developed through work with five frames, hundreds charts, and number frames, which assist students in seeing the numerical pattern when skip counting by five. A variety of representations have been used to help students visualize this pattern.

This work helps students deepen their understanding of operations because each time they say a number in the skip count sequence, they have added another group of five or ten.

Students engage in Mathematical Practice 7 (Look for and express regularity in repeated reasoning) as they notice the pattern in the numbers and apply this understanding to time. Skip counting by fives creates a five-zero pattern in the ones place. Skip counting by tens creates a zero pattern in the ones place. When students understand this pattern, they can apply it to telling time to the nearest five minutes.

**Key vocabulary:**

- counting strips
- five frames
- hundreds chart
- representations
- skip counting

**Special materials needed:**

- counting strips
- five frames
- hundreds chart