2.NBT.1.a: 100 as a Bundle of Ten Tens

I can understand that 100 can be thought of as a bundle of ten tens.

What Your Child Needs to Know

This standard focuses on helping your child understand that 100 can be thought of as a bundle of ten tens. This is a fundamental place value concept that helps students visualize and work with three-digit numbers.

Understanding that 100 equals ten groups of ten is essential for developing number sense and prepares your child for working with larger numbers. This concept builds on your child's previous work with tens and ones in 1st grade and is a stepping stone to understanding the base-ten number system.

Real World Practice

Visual models and hands-on activities

Visual Models

1. Base-Ten Blocks

Use flat hundreds blocks alongside ten rods to show that one hundred block equals ten ten-rods lined up together.

2. Ten-Frame Arrays

Create an array of ten ten-frames (each filled with 10 counters) to show that 10 groups of 10 make 100.

3. Bundled Sticks

Use craft sticks bundled in groups of 10 to show that 10 bundles make 100 individual sticks.

4. Hundred Chart

Use a hundred chart to show that 100 is organized as 10 rows with 10 numbers in each row.

Everyday Activities

1. Money Counting

Use dimes to show that 10 dimes (10 groups of 10 cents) equal 100 cents or one dollar.

2. Building with Blocks

Build structures using exactly 100 blocks, organizing them in 10 groups of 10 to reinforce the concept.

3. 100th Day Activities

When your child's class celebrates the 100th day of school, create collections of 100 items arranged in 10 groups of 10.

4. Counting by Tens

Practice counting by tens to 100 (10, 20, 30... 100) while using fingers to keep track of how many tens have been counted.

Quick Checks

Strategies and quick activities

Strategies When Your Child Struggles

1. Start with Concrete Objects

Use physical objects that can be grouped in tens (like beans, buttons, or small blocks) before moving to pictures or numbers.

2. Connect to Counting by Tens

Practice counting by tens to 100, using objects to represent each group of ten as you count.

3. Use Visual Supports

Draw pictures showing 10 groups with 10 items in each group to reinforce the concept visually.

4. Make Real-Life Connections

Point out examples of 10 tens in everyday life, such as 10 dimes making a dollar or 10 rows of 10 in an egg carton.

5. Break It Down

If 100 seems overwhelming, start with smaller numbers like showing that 2 tens make 20, 3 tens make 30, and build up to 10 tens.

5-Minute Practice Activities

Activity 1: Ten-Group Challenge

Give your child 100 small objects and ask them to organize them into exactly 10 equal groups. Then have them count to verify there are 10 in each group.

Activity 2: Dime Exchange

Show your child 10 dimes and explain that each is worth 10 cents. Count by tens to show that 10 dimes equal 100 cents or one dollar.

Activity 3: Hundred Chart Hunt

Using a hundred chart, have your child identify how many rows of 10 make up the chart, reinforcing that 10 tens make 100.

Activity 4: Bundle Counting

Create 10 bundles with 10 items in each (straws, toothpicks, etc.). Have your child count the bundles by tens to reach 100.

Check Progress

Track improvement

By the middle of the year, your child should:

  • Recognize that 100 can be represented as 10 groups of 10
  • Count by tens to 100 and understand each count represents a group of 10
  • Use base-ten blocks or drawings to show 100 as 10 tens
  • Explain in simple terms that 100 equals 10 tens

By the end of the year, your child should:

  • Fluently recognize and represent 100 as 10 tens in various contexts
  • Apply this understanding when working with three-digit numbers
  • Connect this concept to money (10 dimes = 100 cents = $1)
  • Use this understanding to help with addition and subtraction of two-digit numbers

Mastery Signs

Your child understands this concept when they can:

  • Consistently explain that 100 equals 10 tens without prompting
  • Demonstrate with objects or drawings that 10 groups of 10 make 100
  • Apply this understanding when solving problems with hundreds
  • Make connections between this concept and other place value concepts
  • Recognize examples of 10 tens making 100 in everyday situations

Differentiation

Support for all learning levels

Below Grade Level

Practice problems focusing on counting by tens and grouping objects into tens before connecting to the concept of 100 as ten tens.

Download Practice Worksheet

At Grade Level

Standard practice with representing 100 as ten tens using various models and connecting to place value concepts.

Download Grade Level Worksheet

Above Grade Level

Advanced practice applying the concept of 100 as ten tens to solve problems with larger numbers and exploring patterns in the base-ten system.

Download Challenge Worksheet