Author:
Elizabeth Silva
Subject:
Mathematics
Material Type:
Lesson
Level:
Lower Primary
1, 2
Tags:
Difference, Game-based Learning, Related Facts, Subtraction
Language:
English
Media Formats:

# Grade 1 & 2 Roll and Sort Difference

## Overview

As a teacher your goal is to provide practice using carefully selected strategies. Through encouragement you can provide experiences for students to develop efficient strategies. Use the following strategies to develop the basic addition and subtraction facts.  By the end of first grade, students should be able to count on to find the difference.  For the difference of 7 - 4, start with 4 and count on 5, 6, 7.  This shows that 7 - 4 = three.  Another strategy is to use related facts to find the difference.  If students use a related fact, 4 + ___ = 7, then they’ll know 7 – 4 = three.   Another strategy would be the near doubles strategy.  Using the same problem 7 - 4, add 4 + 4 to get 8 and then subtract 1 to get seven.

By providing experiences to learn these strategies, students will develop number sense and understand how to compose and decompose numbers.  This in turn will help students to develop basic fact fluency and learn while having fun playing a game.

# Roll and Sort Difference

This is an ongoing lesson.  It should be completed 2 or 3 times per month.

# Topic:

(Grade 1) Play a dice game to develop fluency with addition and subtraction within 10 through practice.

(Grade 2) Play a dice game to develop fluency with addition and subtraction within 20 through practice.

# SOL:

1.7b         The student will demonstrate fluency with addition and subtraction within 10.

2.5b         The student will demonstrate fluency with addition and subtraction within 20.

# Materials

• Clear or solid colored shower curtain approximately 70 x 70 inches
• Bright colored tape
• 6 pages of cardstock
• 2 extremely large dice (one with numbers and one with dots)
• Large index cards (1 pkg)
• Roll and Sort Difference template - classroom set (attached)
• Dot dice (1 per pair of students; #1 - 6)
• Blank dice (1 per pair of students)

# Vocabulary

add, addition, combine or joined, difference, equals (=) sign, minus, minus (–) sign, number sentence, parts, plus (+) sign, put together, related fact, subtract, subtraction, sum, take apart, whole

Student/Teacher Actions: What should students be doing? What should teachers be doing?

Teacher Preparation: You are going to create a floor mat using the shower curtain.

• Using the colored tape, divide the curtain into 12 equivalent columns and 6 equivalent rows. (See the example at the end of the lesson.)
• The bottom row of the floor mat will represent the numbers 0 - 11.  Cut each piece of cardstock in half.  Write each number on a different piece of cardstock. (See last page of lesson.)
• Using the large index cards, write the number 0 on five of the cards and repeat the process for the numbers 1 – 11.
• On the blank 6 sided dice, write the numbers 2, 3, 4, 6, 8, 10.

1. The purpose of this lesson is to introduce a game for the students to play in pairs during centers using the template at the end of the lesson.  To introduce the game, set out the mat and invite the class to sit around the perimeter of the mat.
2. Choose a student to roll the dice and tell the difference of the 2 numbers (Example: 10 and 6 are rolled) by subtracting the smaller number from the larger number (Example: 10 – 6 = 4).  Choose another student to place the correct index card in the first rectangle above the difference (answer is 4) of the 2 numbers (10 and 6) rolled. I have used different kinds of dice over the years.  I have used inflatable dice and I have also used dice made from foam.  I also place a large square shaped piece of bulletin board paper next to the mat for students to roll the dice.
3. Choose another student to roll the dice and another student to place the correct index card in the appropriate column.
4. Continue the process until several rolls have been completed and ask the class what difference will be rolled next.  Guide students to use patterns from the mat to decide which number will be rolled and why that number was chosen.  This is a good strategy to find out the problem solving and reasoning ability of students.
5. Continue playing the game until a column is filled.
6.  Wrap up the whole group session by asking the following questions.  How many times was the difference of ______ rolled?  How do you know?  Ask these questions for the difference that was rolled the most and the least.  Which number is the largest?  Which number is the least?
7. Pass out the Roll and Sort Subtraction template to each student.  Group the students in pairs and give each pair a dot die and a number die.  The students take turns rolling the dice and writing each difference rolled in the correct column on their own paper.  Walk around the classroom and ask the students the questions in #6 above.  Tell the students that when one column is filled, circle the column and continue playing.  Students should play until most pairs have 1 column filled.
8. Bring the class back together and record the data from the students for numbers that were filled first between each pair.  Ask the students questions from #6 to collect data on student understanding.

Roll and Sort Difference Template

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