Today we are going to look at another mental math strategy. This one is called Making Tens. This may also sound familiar since you did something similar last year in Primary 1. This strategy can help us with addition and subtraction, but let's first review the combinations of 10. I have a chart here called Making Tens. We are going to name all the combinations of numbers that make 10 when we add them together. This means that if we have a 1 here (point to 1), what other number, when added to the 1, will make 10?
Today we are going to look at another mental math strategy. This one is called Making Tens. This may also sound familiar since you did something similar last year in Primary 1. This strategy can help us with addition and subtraction, but let's first review the combinations of 10. I have a chart here called Making Tens. We are going to name all the combinations of numbers that make 10 when we add them together. This means that if we have a 1 here (point to 1), what other number, when added to the 1, will make 10?
Math4u grade 2 first term
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ولمشاهدة شرح دروس ماث جريد 2 الترم الاول المنهج الجديد بأسلوب سهل وبسيط أضغط على الرابط التالى
ولمشاهدة شرح دروس ماث جريد 2 الترم الاول المنهج الجديد بأسلوب سهل وبسيط
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Mathematics Teacher`s Guide primary 2
Math primary 2 first term lesson 14
Learn (40 minutes)
Learn (40 minutes)
Directions
Directions
Note to the Teacher: In Primary 1, students used ten frames. The first part of this lesson is a review of all combinations of 10. If students need an additional visual, you can remind them or have them use ten frames. Ten frames may also help students who have a difficult time quickly making tens during subtraction and addition. Make them available as a resource to students if they need them.
TEACHER DO: Use Calling Sticks to select a student to answer. If they do not give the correct answer (9), ask them to show you on their fingers by holding up 1 finger and then counting the rest of their fingers to make 10.
TEACHER SAY: Great. 9 and 1 make 10.
TEACHER DO: Write 9 on the Making Tens chart.
TEACHER SAY: Open your student book to the page Lesson 14: Apply. Work with your Shoulder Partner for 2 minutes to come up with other combinations that make 10. Record your thinking in your student book.
STUDENTS DO: Turn to their Shoulder Partner and name as many combinations as they can that make 10.
TEACHER DO: Listen to students as they talk with their partner to make sure they are on the right track. If students are confused, encourage them to use their fingers to find the combinations of 10. Give student partners approximately 2 minutes and then use an Attention Getting Signal to bring the group back together.
TEACHER SAY: Let’s fill in the rest of our chart. If one of your friends says a combination you do not have, add it to your chart in your student book.
TEACHER DO: Use Calling Sticks to select students to help complete the class chart.
STUDENTS DO: Selected students share combinations that make ten until the chart is completed. All students complete the Making Tens chart in the student book.
2.TEACHER SAY: Now I will teach you how to use this information to help you do some mental math.
TEACHER DO: Write 6 + 8 = on the board.
TEACHER SAY: We can make tens with either addend. I will choose the 6. I know that 6 + 4 makes 10.
TEACHER DO: Add to the problem on the board to show your thinking.
6 + 8 = .....
6 + 4 = 10
TEACHER SAY: If I take that 4 away from the 8, that leaves 4, because 4 + 4 equals 8.
TEACHER DO: Add to the problem on the board to show your thinking.
6 + 8 = ....
6 + 4 = 10
4
TEACHER SAY: I add that 4 to the 10 and I have the answer: 14.
TEACHER DO: Add to the problem on the board to show your thinking.
6 + 8 = .....
6 + 4 = 10
4
10 + 4 = 14
TEACHER SAY: Let me show you one more example and then we will talk about it together.
TEACHER DO: Write 9 + 3 = on the board.
TEACHER SAY: We could start with either addend again, but it is easier for me to make 10
with the biggest number here. I know 9 + 1 = 10.
TEACHER DO: Add to the problem on the board to show your thinking.
9 + 3 = .....
9 + 1 = 10
TEACHER DO: Add to the problem on the board to show your thinking.
9 + 3 = .....
9 + 1 = 10
2
TEACHER SAY: Now I can add that 2 to the 10 and I have the answer.
TEACHER DO: Add to the problem on the board to show your thinking.
9 + 3 = .....
9 + 1 = 10
2
10 + 2 = 12
TEACHER SAY: Turn and Talk to your Shoulder Partner about what I just did and how I used the mental math strategy Making Tens to solve this problem.
STUDENTS DO: Talk with their Shoulder Partner about the Making Tens mental math strategy.
TEACHER DO: Listen as students talk to each other. Note who has difficulty understanding how one number can break down into two parts (for example, in the last problem, 3 broke down into 1 and 2).
TEACHER SAY: I would like to give two of you a chance to share what you talked about with your Shoulder Partner.
TEACHER DO: Use Calling Sticks (or call on two students you heard talking during Shoulder Partner time) and have two students share what they noticed about the making tens strategy.
3.TEACHER SAY: You are doing a wonderful job with this tricky strategy. We are now going to see how we can use the same strategy for subtraction problems, and then you will get some time to try this with a partner.
TEACHER DO: Write 15 – 7 = on the board.
TEACHER SAY: We can also use the Making Tens strategy in subtraction problems. To get from 15 to 10, I need to subtract 5. I know this quickly because I remember when we added tens the other day, the digit in the Ones place stays the same and the digit in the Tens place goes up or down 1. If I already take away 5 to get to 10, then I have 2 left from the 7, so 10 – 2 = 8. What I did here was 15 – 5 – 2 = 8.
TEACHER SAY: Let's try one together and then you will work with a partner.
TEACHER DO: Write 14 – 6 = on the board.
TEACHER SAY: What is the fi rst thing we should do in this problem to apply our mental math strategy?
TEACHER DO: Use Calling Sticks to call on students. Listen for the answer "Make ten by subtracting 4 from 14" (or something similar).
STUDENTS DO: Selected students answer the question.
TEACHER SAY: Th at is right. Since we are making tens, we start with 14 and have to subtract 4 to get to 10. What should we do next?
TEACHER DO: Use Calling Sticks to call on students. Listen for the answer "Take 2 more away from 10 because 2 + 4 is 6" (or something similar).
STUDENTS DO: Selected students answer the question.
TEACHER SAY: You are on a roll. Yes, so we will take 4 away from 14 to get to 10 and then take 2 more away. So, 10 – 2 is, what, everyone?
STUDENTS DO: Call out the correct answer (8).
4.TEACHER SAY: You will now get to practice the strategy in your student book. Open it to the page Lesson 14: Apply Continued. You may work on your own or with your Shoulder Partner to solve the math problems. Try using the Making Tens mental math strategy since that is what we have been learning. It is okay if you are not perfect at using the strategy yet. We are learning together.
STUDENTS DO: Work independently or with their Shoulder Partner to solve problems for this lesson using the Making Tens strategy.
