Explore Together

Understand Tens Guided Instruction

Show 20

Step By Step Count cubes. Make tens, Color. Write how

many tens Explain the directions at the top of the page

Have children follow the model by counting

out 20 cubes and making groups of 10. Ask

why 2 groups of cubes are colored. Ensure

that children make the connection between

the physical model and the picture.

2 tens Allow children time to complete

Problems 1-3. Watch to make sure they

Show 30. Show 40 Show 50. count, color, and record the number of tens,

not the number of cubes, on the lines.

Discuss the structure of the numbers 20, 30,

40,50, connecting each one to the number

of tens recorded. Make sure children

understand that the zero shows there are

3tens 4tens 5 tens only tens and no extra ones

Write the number 30 on the board and cover

the zero. Ask: IflI told you to show this number

of cubes, what would you do?Children

should see that without the zero, the Ana counts 3 tens. Micah counts 20 ones. Which is more?

number is read as 3 ones, not as 3 tens

Mathematical Discourse 3

Visual Model Mathematical Discourse Talk About It

Recognize rows of a hundreds chart 3 How could you see that 40 is more than Read the Talk About It question aloud

as tens 30 just by looking at thenumbers? Encourage children to justify their decision

Look for an understanding that the Materials For each child: Hundreds Ask Mathematical Discourse question 4to

digits 3 and 4 in 30 and 40 indicate a extend the idea of comparing tens Chart (Activity Sheet 19), crayons

number of tens. Since 4 is more than 3 Display a hundreds chart. Ask children Mathematical Discourse 4

4 tens or 40 is more than to find the row of squares showing 1- -10

3 tens or 30 Visual Model on their own charts and color it.

Demonstrate on the displayed chart, 4 How did you decide whether Ana or

Have children shade in the next row of Micah has more cubes? Ready

Mathematics PRACTICE AND PROBLEM SOLVING

ten with a different color. Ask how many Some children might suggest building

rows are shaded and how many squares each group of cubes and counting Assign Practice and Problem Solving

are shaded. Encourage children to them. Others may suggest thinking of pages 157- -158 after students have

justify their answers by counting, or by 3 tens as 30 ones and comparing completed this section

recognizing that the numbers on the 20 ones to 30 ones or thinking of 20 as

chart tell how many in all 2 tens and comparing 3tens to 2 tens.

Continue to have children shade in rows

and find totals. Discuss how each row is

like a ten they made with connecting

cubes

Point out that the numbers in the

rightmost column are the numbers you

say when you count by tens

113 Lesson 17 Understand Tens OCurriculum Associates, LLC Copying is not permitted