What's My Clue? (Adding and Subtracting)

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Objective

SWBAT identify clue words to help decide if they should add or subtract.

Big Idea

Clue words can help you determine when to add or subtract.

Direct Instruction

15 minutes

In this What's My Clue Video, I introduce the lesson for today.  

Students need to know when to add and subtract.  I feel that if they learn key words to help them, then all students can master solving real-world problems.  In this lesson, I will let the students know that to become expert word-problem solvers, all they need to do is look for clue words.  Once they find the clue words, they can fluently add or subtract any multi-digit numbers using the standard algorithm (4.NBT.4).

 To begin, I show the Clue Words for Adding and Subtracting power point on the Smart board.  I give the students a few minutes to study the group of words.  I give a practice problem (Practice Problem - What's My Clue) and see if the students can find the clue.

 

Sample:

Tess had 112 pencils.  She gave some to her friend.  She now has 34 pencils.  How many pencils did Tess give away?

Ask the students a series of questions to help them solve the problem.

1.  How many pencils did Tess have at first?

2.  How many pencils does she have now?

3.  Did the number go up or down?

4.  What clue word(s) do you see?

 

From answering the questions, the students should realize that the number went down.  Therefore, they need to subtract.  The clue word for this problem is "gave."  Tell the students that whenever someone gives something away, their number will decrease.  That is a clue to  subtract.

Group or Partner Activity

20 minutes

To give the students practice on the skill, I let them work as pairs.  I like for my students to work in small groups because it allows all of the students a chance to be heard and share their thoughts or justifications for their answers (MP3).  Also, they must communicate precisely to others within their groups (MP6) using math terminology appropariate for the skill.

I give each group a copy of the clue words.  They should use this list of clues to help them solve the real-world problems (MP5).  In their groups, the students work together using a Group Activity What's My Clue sheet with real world problems.  They must reason abstractly by decontextualizing the information and representing it in addition and subtraction equations (MP2).  The students should make sense of the problem (MP1) by discussing the clues and solving them using the standard algorithm.

Independent Activity

15 minutes

To give me a clear understanding of what each student knows, the students will do an independent assignment.   I need to assess students independently to make sure they are all comprehending the skill.   I will put a problem on the Smart board for the students to work (see attached resource).  The students will use paper and pencil to solve the problem.  I will walk around to visually assess the students understanding, keeping track of all students who I will work with in small group for remediation.

Independent Assignment What's My Clue

Terry's mom went shopping 138 days last year.  Peter's mom went shopping 76 days last year.  How many more days did Terry's mom go shopping than Peter's mom?

Clue word:  ______________

Equation:  _______________


To close the lesson, I have one or two students share their answers.  This gives those students who still do not understand another opportunity to learn it.  I like to use my document camera to show the students' work during this time.  Some students do not understand what is being said, but understand clearly when the work is put up for them to see.

The closure is also the time for students to ask any questions that they may have for me.  I do no like to end my class with students being confused about anything.