Mathematics · Kindergarten · Numbers in Our World · Weeks 1-9

Counting to 100 by Ones and Tens

Counting to 100 by ones and by tens.

• Common Core State Standards
• CCSS.Math.Content.K.CC.A.1

About This Topic

Counting to 100 is a landmark skill in Kindergarten, and CCSS.Math.Content.K.CC.A.1 sets the expectation that students can count by both ones and tens. Counting by ones builds the sequential understanding of the number system, while counting by tens introduces the first glimpse of grouping by place value. These two modes of counting teach different things: ones build sequence knowledge, tens build skip-pattern fluency.

The hundreds chart is the primary tool for this standard. It makes the structure of the number system visible, showing how ones change across each row and tens reset at the start of a new row. Students who can count by tens on a hundreds chart are building intuition that will support base-ten understanding in first and second grade.

Active learning approaches transform what could be rote recitation into meaningful exploration. Movement-based counting, rhythm and pattern games, and partner-based hundreds chart investigations all give students authentic reasons to count to large numbers and notice the structures those numbers contain. Students who discover the patterns themselves retain them far more reliably than those who are told what to notice.

Key Questions

1. Compare counting by ones to counting by tens to 100.
2. Explain the advantage of counting by tens when counting a large group of objects.
3. Predict the next number when counting by tens from 30.

Learning Objectives

• Count to 100 by ones, identifying the next number in a sequence.
• Count to 100 by tens, identifying the next number in a sequence.
• Compare the process of counting by ones versus counting by tens to reach 100.
• Explain why counting by tens is more efficient for large quantities.
• Predict the next number when counting by tens from a given number up to 100.

Before You Start

Counting to 20 by Ones

Why: Students need a solid foundation in counting small sets of objects by ones before extending this skill to larger numbers.

Number Recognition (0-20)

Why: Recognizing the numerals is essential for both counting by ones and identifying the numbers when counting by tens.

Key Vocabulary

Count by ones	To say or list numbers in sequential order, increasing by one each time, such as 1, 2, 3.
Count by tens	To say or list numbers in a skip-counting pattern, increasing by ten each time, such as 10, 20, 30.
Hundreds chart	A grid showing numbers from 1 to 100, arranged in rows and columns, which helps visualize number patterns.
Sequence	A set of numbers that follow a specific order or pattern.

Watch Out for These Misconceptions

Common Misconception

Students can recite counting by tens to 100 as a memorized chant but do not understand that each step represents ten more than the last.

What to Teach Instead

Pair the tens chant with physical grouping: bundles of ten sticks, tens blocks, or groups of ten counters. Each step in the chant should correspond to adding one more physical group of ten. The chant alone is a performance skill; paired with grouping, it becomes a conceptual tool.

Common Misconception

Students think counting by tens is 'fewer numbers' but do not see the mathematical relationship between the ones sequence and the tens sequence within it.

What to Teach Instead

Place the tens sequence alongside the full ones sequence on a hundreds chart and ask what patterns students notice. The connection between 30 and 31, 32, 33... shows students that the tens are embedded within the full sequence, not a separate counting system.

Common Misconception

Students lose track at decade transitions, getting to 29 and then saying 30, 41, 42... instead of 30, 31, 32.

What to Teach Instead

The transition from 29 to 30 requires holding both the ones sequence and the decade structure simultaneously. Extra focused practice at each transition point, using the hundreds chart as a visual guide, addresses this directly and efficiently.

Active Learning Ideas

Whole Class: Count and Move

Students stand in a circle and count by ones to 100, each student saying the next number and stepping to the right. On every tenth number, the whole class claps loudly. After reaching 100, repeat counting only the clap numbers (10, 20, 30...) to make the tens pattern explicit through movement and sound.

15 min·Whole Class

Stations Rotation: Hundreds Chart Mysteries

Cover several numbers on a printed hundreds chart with sticky notes. Students work in small groups to figure out the hidden numbers using the patterns visible in uncovered rows and columns. Groups record their answers and reasoning before removing the sticky notes to check.

25 min·Small Groups

Think-Pair-Share: Ones or Tens?

Present a jar of 40 small objects. Ask partners to predict which would be faster: counting by ones or by tens? Both methods are then tried with the actual objects. Pairs compare the experience and discuss when counting by tens is more useful than counting by ones.

20 min·Pairs

Gallery Walk: Pattern Posters

Post strips of paper showing the counting-by-tens sequence (10, 20, 30...) with several numbers covered. Students walk through, fill in missing numbers, and add one pattern observation: what do all these numbers have in common? Discuss observations as a class at the end.

15 min·Pairs

Real-World Connections

• Cashiers at a grocery store count money. They might count bills by tens (e.g., ten dollar bills) to quickly determine a total amount owed or change given.
• Event planners often count guests or supplies. Counting chairs by tens for a large party or seating arrangement makes the task faster than counting each one individually.

Assessment Ideas

Quick Check

Provide students with a blank hundreds chart. Ask them to color the numbers when counting by ones up to 20. Then, ask them to circle the numbers when counting by tens up to 100.

Discussion Prompt

Present students with a scenario: 'Imagine you have 50 toy cars to count. Would it be faster to count them one by one, or to count them in groups of ten? Explain why.' Listen for student reasoning about efficiency.

Exit Ticket

Give each student a card with a starting number (e.g., 30). Ask them to write the next three numbers when counting by tens. Then, ask them to write the next three numbers when counting by ones.

Frequently Asked Questions

What is the difference between counting by ones and counting by tens to 100?

Counting by ones means saying each number in sequence (1, 2, 3...) through to 100. Counting by tens means saying every tenth number (10, 20, 30...) through to 100. Both are valid ways to count to 100, but they teach different things: ones build sequence knowledge, tens build skip-pattern fluency and early place value intuition.

How does a hundreds chart support counting to 100?

A hundreds chart arranges numbers 1 through 100 in a 10-column grid where each row starts at a new decade. This layout makes patterns visible: all tens end a row, ones change across a row, and counting down a column always adds 10. These visible patterns support both ones and tens counting and give students a spatial model for the number system.

When should kindergartners be able to count to 100?

CCSS.K.CC.A.1 expects this by the end of Kindergarten. Most programs build toward it across the full year, adding chunks of numbers as fluency develops. Counting by tens typically becomes fluent before counting by ones to 100 because it is a shorter, more rhythmic sequence, and both are reinforced daily through classroom routines like calendar time.

How does active learning support counting to large numbers?

Counting to 100 can feel meaningless when practiced only through recitation. Active structures like movement counts, where each number corresponds to a physical action, and group investigations of the hundreds chart give students a reason to use large numbers and discover the patterns themselves. Students who discover that all tens numbers share the same ones digit retain the structure better than students who are told it directly.