In this unit, students will continue their work on the counting sequence to 100 and will be introduced to the pattern of counting by tens. This will be foundational in their understanding that a twodigit number such as 53 is made up of 53 ones or 5 tens and 3 ones. This notion relies heavily on the idea that a ten is both ten ones and a ten.
Key Concepts:
 The number of objects in a collection is the same no matter how it is counted.
 We can count larger sets of objects by grouping, then counting by tens.
 The number sequence remains the same regardless of the starting number.
Prior Knowledge Needed:
 Organize objects and count them by ones effectively.
 Understand that the last number name said tells the number of objects counted.
 Classify and count objects
 Rote count from 150.
Units on the Horizon:
 Developing foundations of place value: understanding teen numbers as being composed of ten ones and some more ones; (Grade K, Unit 14: K.NBT.A.1)
 Understanding Ten Ones Make a Ten; (Grade 1, Unit 1: 1.OA.C.6)
 Exploring quantities to 99; (Grade 1, Unit 4: 1.NBT.A.1)
Lessons

Lesson objective: Count a collection two different ways. Students bring prior knowledge of rote counting within 50 from K.CC.A.1. This prior knowledge is extended to counting within 100 by ones and tens as students practice counting larger collections o...

Lesson objective: Count a collection by tens to tell how many dots there are. This lesson helps to build fluency with counting. Ten frames are used here because they support students in grouping ten ones into one bundle of ten. This work develops studen...

Lesson objective: Understand that we can begin counting at a number other than one within a known counting sequence. Students bring prior knowledge of number names and the count sequence from K.CC.A.1. This prior knowledge is extended to counting forwar...

Lesson objective: Count on from a number other than one. This lesson helps to build fluency with counting on from a number other than one (up to 100). A number chart is used here because it supports the student in remembering the counting sequence. This...

Lesson objective: Count on from a number other than one. This lesson helps to apply counting by tens (up to 100) to a realworld situation. Filled tenframes are used here because they support the student in remembering the counting by tens sequence. Th...