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## Take It Away: Minus and Subtract!

### Step-by-Step Procedure

Session 1:

1. Students should have had addition lessons and know the importance of numbers. So consider the following questions as a review session and an introduction to Subtraction. Ask the students, "What are numbers?"; "Why do we have so many names for numbers?" "Can we work without numbers?"; "Can we shop without numbers?" "Can we earn money without numbers?" "Can we have birth dates without numbers?" "Can we have a calendar without numbers?"
2. Observe students who can communicate the value of having numbers and the concept of numbers each having an intrinsic value.
3. Write their responses on a new SMART Board page and save. Inform them that for homework they have to consciously think about numbers and how they help us at home and notice how numbers are used on the roads when going home on the bus or by car. Xerox the attached sheet Where are numbers... for their homework assignment. Then have the students relate to the whole class their discoveries as you write them on the SMART Board.

Session 2:

1. Bring up the SMART Notebook file Number Lines. Show them where numbers 'live" and inform them that the numbers also "know" their next door neighbors. Ask the students what neighbor number is before (5)? What mystery number is 2 numbers before (5)? Continue to ask questions about numbers and then reverse the role. Have students come up with their own questions. Model again what to ask: "What number is before (9) or what number is after (7)?"
2. Xerox the flashcards before/after sheets provided below. Inform the children that they will play a game of Around-the-Word. Line the students in two rows facing you. You will flash a card to the 2 children in front of you and the first child to answer the correct answer goes back at the end of the line, the loser goes back to the seat. You continue until there is one winner.

Session 3:

1. Tell the students that using the number line is like visiting friends. It can be fun especially when they don't live too far away.
2. Ask these questions: "How many of you are allowed to walk to your friend's house?"; "How many of you have friends who come to visit you?"
3. Tell them that numbers like to visit other numbers but they follow directions.
4. Bring up the SMART Board lessons on rules for subtraction SMART Notebook file Rules for Subtraction. Each notebook page will allow you to input your ideas to teach how important it is to follow the signs in a number sentence.

Session 4:

Now the fun part begins.

TIP: You can open all 4 SMART Board lessons but keep them minimized at the bottom of your computer screen, on the task bar. Click on the lesson you need easily.

1. Bring up the SMART Board Subtract and Add Signs Lesson. Model and say for example, "Let's take a look at the number 9. The number 9 is much older than little 2. Therefore, the number 9 will walk back two steps to see little 2. Where did we end up? We found that the difference to 9 - 2 is 7."
2. Continue to model and verbalize, "Little 2 is too small to visit 9. Would your mom send you out of the house to visit 9 who lives 9 houses down the road? No. Yet, take a look at the subtraction sentence, 9-7=_," Say, "Number 7 can visit 9 because mom trusts 7 to go to 9's house. Now count the steps to get to number 9 from 7". Say, " 8, 9, those were two steps and don't go any further. Then 7 has to call mom up and say, "It took me 2 steps to get to 9's house." The difference between 9 and 7 is 2!"

The SMART Board Subtraction Lesson has many pages already set up for practice and review.

• Number Lines.notebook
• Rules for Subtraction Problems.notebook
• Subtraction Lesson.notebook
• Subtract and add signs Lesson.notebook
• Where are numbers important.doc
• ### Credits

• http://www.animationfactory.com/
• http://www.barrysclipart.com/barrysclipart.com/
• http://www.tequipment.com/

### Duration of Lesson

Suggested time of 60-minutes per day for four days. The length and duration will depend on your assessments.

Observe the following: How careful are the children at following the signs? If children have not internalized the importance of following the dictates of math signs, then have a follow up and present a lesson about the importance of signs in addition and subtraction problems. Use the SMART Board Subtract and Add Sign Lesson to reinforce the idea of looking at signs and solve accordingly.
Students should be encouraged to engage in math games, hands on activities and manipulatives that are relevant to the concept of subtraction.

### Pre-Assessment

Students come into first grade classrooms with various abilities and you need to know where to start with your teaching of this very difficult concept. Some very basic steps will enable you to put children in general areas of expertise or lack thereof.

Use the teacher's assessment sheet to aid you in pooling children together by ability and or by interests. The assessment does not have to be long but it should lend some validity if it has the components you are basing your groups on.

Some ideas are:

• The student knows what an addition sentence is.
• The student knows immediately what number comes before and after when a targeted number is shown. (If there is lots of wait time here, the student has not mastered the placement of numbers yet.)
• The student knows how to set up a subtraction sentence.
• What are some questions that can be asked of a subtraction sentence?
• assessment - Subtraction.doc
• ### Learning Objectives

• Students will learn the vocabulary words for subtraction.
• Students will know how to count back and count on from any given number.
• Students will know that a subtraction sentence has a minuend minus a subtrahend which equals the difference.
• Students will know that the minuend is always the larger number or the first number in a subtraction problem.
• Children will know that the subtrahend is the number that takes away from the minuend.
• Students will know that the answer to a subtraction sentence is called the difference.

### Assessment

Use any subtraction problems worksheets that you may already have or use the attached Post Assessment sheet. With your class roster handy, write the numbers 1-10, in a row, next to each child's name. Cut the sheet into 10 boxes and hand one box to each child. Each box has a number and a subtraction problem. Then hand each student a sheet of paper with the number 1-10 on it. You inform the students not write in the paper box but to solve and write the answer on the numbered sheet that corresponds to the boxed number. This activity will have children looking for more boxes. As children finish, hand the boxes to other children until all have had their ten problems. Keep the rest of the classroom working with the SMART board on subtraction problems. As children are finished with their problems, call them up to see you one at a time, ask them to show you how they solved their problem. If the solution is correct, put a check mark next to the number by their names. Children can verbalize what they know or not know. Use the attached Subtraction Assessment.

• Post assessment.doc
• subtraction assessment.doc
• ### Vocabulary

There is a need to have all students use the same vocabulary words when working on a common goal of learning a new concept. There are so many ways to make learning new words fun.

1. Flashcards:

Attached are sheets with math words. Xerox the words on card stock, oak tags, or glue the sheets on construction paper. Attached you will find a blank sheet where you can add your own words. Children can cut them apart, you punch holes and they can hang them on little rings. Children can use them at a center or at their seats. Click on the following links to get access to wonderful flashcards:

1. http://www.scholastic.com/kids/homework/flashcards.htm
2. http://www.janbrett.com/games/subtraction_flash_cards_main.htm

<----before, after---->,count back, count on, number, digit, subtract, take away, equal sign, 10 numbers on 10 cards with the word before on each card, do the same for another 10 numbers with the word after.

2. Word Wall:

Duplicate a set for the wall from the children's set. Place the words on your math board. Then, in a darkened classroom, allow the children to use a flashlight to find answers to your questions. For example: Say, "2 -2 is zero. Find the word that has the same meaning as is."

• Flashcards math words.doc
• Blank Flashcards.doc
• Before _ Flashcards.doc
• ### Materials

• cardstock or construction sheets
• chicken rings or metallic rings
• individual number lines 0-10