The purpose of this activity is for students to create a collection of 65 using only 5 towers of 10 and single cubes. Students are told that they can’t create any new towers or take apart any towers. Students recognize that there are only 5 tens and consider how many ones are needed to get to 65. Students may count on from 50 to 65.  Students may also apply what they have learned in previous lessons to determine they need 1 more ten and 5 more ones, or 15 (MP2). As students represent their collection, they may show the number of towers of 10 they used and how many ones, including 5 tens and 15 ones, or that they grouped 10 of the ones in some way. This includes clearly marking a group of 10 ones.

Students may label their drawings using numbers, a combination of numbers and words, or expressions (MP6).

• Invite previously identified students to share.
• “How do each of these representations show 65? How are these representations alike? How are they different?” (They all show some tens and some ones. One shows 15 ones and the other shows 10 ones in a group and then 5 more ones. One shows an expression and the others don't.)

The purpose of this activity is for students to represent 37 with tens and ones in different ways. It is not necessary that students find all the ways to represent 37. Students should see that the number can be represented with different amounts of tens and ones. Students are given connecting cubes in towers of 10 and singles, and they represent their thinking on paper using drawings, numbers, or words. Some students may initially represent 37 using 3 tens and 7 ones. Then they notice that they can decompose a tower of 10 into 10 singles and have 2 tens and 17 ones and use this structure to find other ways. Students may represent 37 as , , etc., which are all ways to represent the number. The Lesson Synthesis focuses on representing 37 with different groups of tens and ones.

• Invite previously identified students to share.
• Record each way students made 37.
• “What do you notice about the ways they made 37?” (They both made 37 in the same ways. One student started with all ones and made 1 ten at a time. The other student started with 3 tens and broke 1 ten apart at a time. Each time a ten was made, there were 10 fewer ones. Each time a 10 was broken apart, there were 10 more ones.)

The purpose of this activity is for students to choose from activities that offer practice working with two-digit numbers. 

• Greatest of Them All
• Get Your Numbers in Order
• Grab and Count

• “How did you work with 2-digit numbers during center time?”