Accepted or not accepted estimation - math grade 2 - lesson 37 - ماث فور يو

we have been working on adding 2-digit numbers by decomposing numbers into Tens and Ones without regrouping. In today’s lesson, we begin to think about how to solve problems when we have more than 9 Ones in the Ones place (though they will not learn regrouping in this lesson).

Math4u grade 2 first term

ماث فور يو جريد 2

math grade 2 first term

شرح دروس ماث جريد 2 الترم الاول المنهج الجديد بأسلوب سهل وبسيط

Mathematics Teacher`s Guide primary 2

$Accepted or not accepted estimation - math grade 2 - lesson 37$

Math primary 2 first term lesson 37

Learn (40 minutes)

Directions

Note to the Teacher: Th is is a direct link to the Calendar Math, where they have practiced regrouping 10 Ones to make 1 Ten.

1.TEACHER DO: Write the following problem on the board with lines below and boxes to decompose, like in previous lessons.

TEACHER SAY: Yesterday we practiced estimating. We have also been practicing decomposing 2-digit numbers into Tens and Ones. Today we will estimate the sum, and then we will break apart the 2-digit numbers to think about what might happen if we have too many Ones in the Ones place. Does anyone think they know what happens if we have too many Ones in the Ones place? Raise your hand.

STUDENTS DO: Raise hands to volunteer. Selected students share their thinking.

TEACHER DO: If any students mention the correct strategy, take note. Otherwise, thank students for sharing their ideas and direct their attention to the problem on the board. Read the problem aloud.

TEACHER SAY: Let’s use place value to estimate the sum. I am going to need helpers.

TEACHER DO: Use Calling Sticks to select a student to help you estimate the sum using place value.

STUDENTS DO: Selected student circles the digits in the Tens place, circles the addition sign, and provides an estimated sum (70).

TEACHER SAY: Thank you for estimating. Now I need a helper to decompose the addends into Tens and Ones.

TEACHER DO: Use Calling Sticks to select a student to decompose the addends into Tens and Ones.

STUDENTS DO: Selected student decomposes both addends into Tens and Ones.

TEACHER SAY: Good job. 37 has 3 Tens and 7 Ones. 48 has 4 Tens and 8 Ones. I am also going to draw a place value picture below the boxes to help us look at this problem in a different way. I will use sticks to represent Tens and dots to represent Ones.

TEACHER DO: Draw Tens sticks and Ones dots for the numbers.

TEACHER SAY: Now that we have decomposed both addends, we are able to add the Tens and Ones together to find the sum. There may be different ways that you would solve this, but let me first show you a way I thought about finding the sum. These numbers have been decomposed into Tens and Ones. 3 Tens plus 4 Tens is 7 Tens. I am going to write 70 on the board and draw 7 Tens sticks.

TEACHER DO: Record 70 on the board under the images and draw 7 Tens sticks. Circle both the 3 Tens and the 4 Tens and then draw a line connecting them to the 70 to visually show the students.

TEACHER SAY: Now if we look at the Ones place, we have 7 and 8. I am going to use the Doubles mental math strategy to solve that problem. I know that 7 + 7 = 14, so 7 + 8 = 15. We have 15 Ones. I am going to write 15 next to the 70, and under it I will draw 1 Tens stick and five Ones dots to represent 15.

TEACHER DO: Record and draw 15 on the board. 70 + 15 = ___.

TEACHER SAY: Now, I can add 70 plus 15. I can see that I have 8 Tens sticks and 5 Ones dots. 70 + 10 + 5 = 85. The sum of 37 + 48 is 85. Raise your hand if you can tell me how I solved that problem. If you get stuck, you can ask a friend for help.

STUDENTS DO: Raise hand to volunteer. Selected students share their summaries. If necessary, ask a friend for help.

TEACHER SAY: Good work. You helped me decompose both of these numbers into Tens and Ones. Then I added the Tens together and the Ones together. Our estimate was 70, but our sum was actually in the 80s. Give me a Thumbs Up if you have an idea why the estimate was so far away from the actual sum.

STUDENTS DO: Give a Thumbs Up to volunteer. Selected students share their thinking.

TEACHER DO: Confirm or correct students’ thinking.

TEACHER SAY: Our estimate was not close because 37 is actually closer to 40 and 48 is closer to 50. That tells us that sometimes the place value strategy will give us a good estimate and sometimes it will not. Open your student book to page Lesson 37: Apply.

STUDENTS DO: Open student book to page Lesson 37: Apply.

4.TEACHER SAY: On this page you will see one problem like the one we did together.

TEACHER DO: Read aloud the directions and the practice problem.

TEACHER SAY: Do you have any questions about the problem?

TEACHER DO: Answer any questions students have about the practice problem.

TEACHER SAY: Work with your Shoulder Partner to solve the practice problem.

STUDENTS DO: Work with their Shoulder Partner to solve the practice problem.

TEACHER DO: Walk around the room and observe students as they discuss and solve the problem. Take note of students who may need additional instruction in estimation, decomposing, or addition. When Learn time is over, use an Attention Getting Signal to bring the group back together.

TEACHER SAY: Nice work today. You did some very challenging math work.

Accepted or not accepted estimation - math grade 2 - lesson 37