Math in the World: Addition and Subtraction

Aim:                 How do you tell the difference between addition and subtraction word problems?

Objective:         The students will be able to distinguish between addition and subtraction word problems through the use of real-world examples.

Materials:      

• Pre-written Addition/Subtraction “Key Words”

• Pennies (one for every child)

• Chart Paper (w/pre-written Addition/Subtraction problems)

• 36 Twizzlers

• Art paper

• Crayons

Do Now:          Each student will be given a penny.  In groups of four, students will answer the questions written on the chalkboard:

                        How much money do you have in all?

If Ms. Paine takes away 2 pennies, how much money will your group have left over?

Once the groups have decided on their answers, Teacher will ask for responses.  Teacher will ask what clues helped children decide whether to add or subtract.

Possible answer: Key words such as “in all,” “take away” and “left over”

Procedure:        Teacher will display three addition phrases/words (“in all, altogether, increase”) and three subtraction phrases (“left over, how many more, decrease”).  Teacher will display an example of each kind of problem pre-written on chart paper*.  Teacher will ask for volunteers to read the word problems and point out the addition/subtraction phrase or word.   Teacher will ask students to look at a word problem for “how many more.” 

If The Scholar Group has 8 Twizzlers and The Girls’ Club has 4 Twizzlers, how many more Twizzlers does The Scholar Group have?

Teacher will then pass out 8 Twizzlers to 3 of the groups and 4 Twizzlers to 3 of the groups.  She will then pair up opposing groups so that they can get together and decide what kind of problem they have.  Teacher will then ask students to find the correct answer.

Activity:            Students will choose one of the word problems previously displayed on chart paper.  Teacher will model how to draw a picture of

the word problem on paper.  Students will use Twizzlers, crayons and imaginative ideas to complete the artistic version of a word problem.

Assessment:   Teacher will informally assess as she walks around room to assist students.  Formally, Teacher will assess student drawings.  The students will have “real world” addition and subtraction problems for homework. 

*Addition Word Problems

Last month, Donna read 4 books.  Her older sister, Karen, read 7 books.  How many books did the sisters read in all? (11 books)

There are 12 students in Ms. Jackson’s after-school class.  There are 8 students in Mr. Wilson’s after-school class.  How many students are there altogether? (20)

On Monday, the temperature reached 84 degrees.  On Tuesday, the temperature increased by 4 degrees.  What was the temperature on Tuesday? (88 degrees)

Subtraction Word Problems

Mrs. Davis made 100 blueberry pies for the school fair.  She sold 89 pies.  How many pies were left over? (11 pies)

Tyrone scored 15 points at the basketball game.  Kenneth scored 12 points.  How many more points did Tyrone score than Kenneth? (3 points)

A man was driving on the highway at 55 miles per hour.  In town, he drives at 30 miles per hour.  How much would his speed decrease? (25 miles per hour)

Sample Student Work (Click on the Thumbnail to enlarge the photo)

For more information, please contact April Paine at april_paine@hotmail.com