# 2 Digit Place Values: Math - Grade 1

Subject: Mathematics

Lesson Objective: To understand that double-digit numbers consist of groupings of tens and ones.

Common Core Standard

• CCSS.MATH.CONTENT.1.NBT.B.2 - Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases:
• CCSS.MATH.CONTENT.1.NBT.B.2.A - 10 can be thought of as a bundle of ten ones — called a "ten."
• CCSS.MATH.CONTENT.1.NBT.B.2.B - The numbers from 11 to 19 are composed of a ten and one, two, three, four, five, six, seven, eight, or nine ones.
• CCSS.MATH.CONTENT.1.NBT.B.2.C - The numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or nine tens (and 0 ones).

## Starter

Say/Do:

• Today we will be learning what two-digit numbers are made up from. Two-digit numbers are very similar to single-digit numbers, but they are made up of groups of tens and groups of ones.
• We are going to be using pipe cleaners in this lesson so we can see exactly how this works.

## Main

Do:

• First, hand out bunches of 59 pipe cleaners to each student. You may cut pipe cleaners in half to conserve both pipe cleaners in space.

Say:

• Alright, class! The first step is to count our pipe cleaners. I want each of you to count out nine pipe cleaners and put them in a pile on your desk.
• Allow students time to count out nine pipe cleaners.
• Now that we have counted out nine pipe cleaners, we need to count out our bunches of tens. Let us count out ten pipe cleaners and place them in a pile.
• Check-in with each student and help them twist tie that bunch together as they finish counting. Have the class repeat this process until you have five bunches of ten, and nine individual pipe cleaners.
• Now that we have our pipe cleaners into our groupings let's talk about what they represent. Each time you have ten pipe cleaners tied together, that bunch represents the first digit. The first digit in a two-digit number always tells us how many tens there are. For example, if our number were 30, the three would tell us that there are three bunches of tens. Just as the first digit tells us the number of tens, the second digit tells us the number of ones. If the number were 24, we would have two bunches of tens and four ones. When we are counting single digits, they stop at nine. When we go from 29 to 30, we do so because we no longer have any single pipe cleaners left from our bunches. Now that we know what the numbers mean, we are going to play a game.
• Every time I reach into the hat, I am going to pull out a number. I will call this number out loud, and you will have 30 seconds to make that number out of your pipe cleaners. Let's do a practice one together. The number I have is 42. Now we should take four of our bunches of ten, put them in a line. Now we need to take two of our ones and put them behind the four bunches. Now the total number of pipe cleaners we have in a line is 42.
• Begin pulling numbers out of your hat and assisting children in creating their pipe cleaner bunches, allowing more time if necessary.

## Feedback

Say:

• Now that we understand how two-digit numbers work and what they mean, you will be able to do so many things. From math, telling the time, multiplying and dividing, you are all on your way to being math superstars.

Written by Amber White

Education World Contributor