Make 100 and 1,000

Overview

In this 30-minute lesson, students compose and decompose three-digit numbers using hundreds, tens, and ones. Building on prior work with place-value blocks and two-digit numbers, students connect concrete models to standard form and expanded form.

Learning intentions

Students will be able to:

• Explain the value of each digit in a three-digit number.
• Decompose a number into hundreds, tens, and ones.
• Write numbers in standard form and expanded form.
• Use place-value language, including compose, decompose, and expanded form.

Success criteria

• I can break a number apart into hundreds, tens, and ones.
• I can show a number in standard form and expanded form.
• I can explain that ten tens can be composed into one hundred.
• I can correctly represent at least 4 of 5 examples.

Curriculum links

• Read and write numbers to 1,000 using base-ten numerals and expanded form.
• Understand that the digits in a three-digit number represent hundreds, tens, and ones, including numbers with zero in one place.
• Use place-value understanding to compare and reason about three-digit numbers.
• Use place-value strategies to compose and decompose numbers.

Lesson structure (30 minutes)

1. 0–4 min · Hook and learning intention. Teacher displays 372 and asks, “How many hundreds, tens, and ones are hiding in this number?” using the opening number puzzle; teacher reads the “I can” statement aloud. Students turn and explain a first idea, then identify the value of each digit.

2. 4–10 min · I do: model decomposition. Teacher builds 372 with base-ten blocks and models placing 300, 70, and 2 cards beneath it, recording 372 = 300 + 70 + 2 on the place-value model slides. Students name the hundreds, tens, and ones and repeat the equation aloud using the sentence frame, “___ has ___ hundreds, ___ tens, and ___ ones.”

3. 10–16 min · We do: compose and decompose. Teacher gives the three students a shared place-value mat and cards for 300, 70, and 2, then guides them to match the cards to 372. On the Smartboard, teacher bundles ten tens into one hundred and asks, “What changed? What stayed the same?” using the bundling demonstration. Students physically move cards, represent the exchange, and explain that ten tens equal one hundred.

4. 16–24 min · You do: guided practice. Teacher distributes the place-value practice worksheet and supports students as they decompose 246, 531, and 708 on a place-value mat. Students show each number in standard and expanded form, using blocks or bundleable straws as needed; teacher models one place at a time for students who need additional support.

5. 24–28 min · Check and discuss. Teacher displays the five multiple-choice assessment questions on the quick-check slides, reads each equation aloud, and asks students to justify answers with blocks, cards, or drawings. Students answer the questions on the worksheet, compare reasoning, and correct any misconception, especially the zero tens in 708 and the meaning of expanded form.

6. 28–30 min · Exit reflection. Teacher asks each student to complete or orally answer the final prompt on the place-value practice worksheet: “Write 604 in expanded form and explain what the 0 means.” Students share one completed equation and rate their confidence with a thumbs-up, sideways thumb, or thumbs-down.

Resources

• the complete place-value slide deck
• the place-value practice worksheet
• Base-ten blocks
• Bundleable straws or straw bundles
• Place-value mats labeled hundreds, tens, and ones
• Number cards and expanded-form cards
• Smartboard or interactive display
• Pencils, crayons, or highlighters
• Three individual whiteboards and markers

Assessment

• During modeling and card work, listen for accurate use of hundreds, tens, and ones and ask, “How do you know?”
• Check the five multiple-choice items: 246 = 200 + 40 + 6; 500 + 30 + 1 = 531; ten tens make one hundred; 708 = 700 + 8; and expanded form shows place values.
• Use the exit response for a quick individual check. Students meet the objective when they correctly show at least 4 of 5 examples and explain the value of a zero place when relevant.

Differentiation

• For support, provide bundleable straws or base-ten blocks, partially completed equations, color-coded place-value columns, and a place-value mat. Model and discuss one place at a time.
• For students with dyslexia, align digits vertically, use consistent colors for hundreds, tens, and ones, read all directions and equations aloud, and allow students to respond with movable cards, pointing, or oral explanations instead of extended writing.
• Keep the group of three interactive: assign rotating roles such as builder, card mover, and explainer, while checking that every student represents each number.
• For students ready for a challenge, ask them to find two different ways to compose 1,000 using hundreds, tens, and ones, or explain why 900 + 100 and 10 hundreds represent the same amount.