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# Let's Stretch the Values! Writing Two-Digit Numbers in Expanded Form

What does it mean to expand a number? Use this lesson plan to help your students understand how to write the expanded form of two-digit numbers.

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Let’s stretch the values! Young mathematicians learn about writing two-digit numbers in expanded form in this helpful math lesson plan. Designed for first graders, this lesson introduces learners to place value by breaking down two-digit numbers into tens and ones (e.g., the number 25 can be understood as 20 and 5). Children will review terms such as single-digit numbers, value, and expanded form, and then practice writing two-digit numbers on charts and in number sentences to help them visualize the different values.

• Students will be able to identify the digit in the ones and tens places of a two-digit number.
• Students will be able to construct a number when told the digits in the tens place and ones place.
• Students will be able to write a two-digit number in expanded form.
(5 minutes)
• Remind students what they already know about single-digit numbers, or the numbers 0 through 9.
• Tell students that today they are going to learn about two-digit numbers and their values.
• Remind students that value means how much a number is worth. Tell your students that they can show value using counters, manipulatives, and base ten blocks.
• Explain to your students that they will learn about place value, or the value of the location of a digit in a number.
(10 minutes)
• On the chart, write tens place and ones place in a t-chart.
• Show the ones place on the right half of the chart, and show the tens place on the left side of the chart.
• Use sticky notes with the digits written on them so you can manipulate the numbers and show different values on the chart.
• Place a 0 in the ten spot. Explain that numbers before 10 have a 0 in front of them because they are less than 10.
• Explain that two-digit numbers are like adding together a tens value with a ones value. For example, with the number 25, explain that it is like having a 20 in the tens place and a 5 in the ones, and 20 + 5 = 25.
• Tell your students that showing the value of two-digit numbers in this way is called expanded form, or a numeric form of writing a number to stretch out the different values into a number sentence.
(10 minutes)
• Write the number 67 on the chart or board.
• Have students discuss how many tens and ones there are with partners.
• Ask a student to explain that 67 is 60 and 7 put together.
• Write these numbers on the board, and ask different students to come up to write the expanded form of the numbers on the chart.
• Give students time to practice writing expanded form on paper or on personal whiteboards.
• Have your students practice with the numbers 29, 83, 74, and 91.
(20 minutes)
• Give your students Quincy's Place Value and Numbers: Expanded Form to practice.
• Enrichment: Include the hundreds place value on the chart. Make the practice more complex by having students practice different forms of the number, such as written form and model form with manipulatives.
• Support: If students need visual supports, use value manipulatives such as base ten blocks. Have students represent the tens values with rods, tens frames, or bundles. For ones, use single manipulatives.
(10 minutes)
• At the end of the lesson, write three numbers on the board.
• Have each student write the expanded form on a sheet of scratch paper with his name on it.
• Collect these assessments.
(5 minutes)
• Review the chart you made during the formal instruction section.
• Summarize the key points and vocabulary.