Basic Concepts of Subtraction Using Counting Backwards Using Crossing Out Prepared by: Arlene V. Lagundino

Overview In this lesson, the pupils will learn about the basic concepts of subtraction using the different modeling methods in subtraction such as counting backwards and by crossing out.

The pupils will also familiarize the basic words used in subtractions which are the subtrahend, minuend, difference, minus and equal sign. They use the symbol (-) minus sign for subtraction.

Subject: Mathematics - I Topic: Subtraction: Counting backwards Crossing Out Time: 6o minutes Period of Teaching: 1 day

Materials/ Teaching Aids Power Point Lesson packages: real objects like straw, beans, marbles, pins, fruits, vegetables and etc. Number lines Pencil, show board Worksheets

Objectives At the end of the lesson, students will be able to: 1. Subtract numbers within 10 by counting backwards. 2. Subtract numbers within 10 by crossing out.

Preparation Prepare the real objects for the manipulative activities. Prepare number cards for 0 – 10 and the minus sign and equals sign.

Prerequisite Skills & Concept Children should be proficient in counting and recognizing numbers to ten. They should also have experienced finding sums to 10.

Procedures 1. Motivation/Getting Their Attention: Watch the video in the youtube. NqG4ChKShI&feature=related Tie to previous learning: This lesson will connect to the previous learning of addition.

2. Introduce the first method by counting backward using number line. Follow the link: L105 L105

3. Using number line chart, do counting backwardsactivity bin/nl.cgi?A1=c&A2=0&A3=4&A4=[4][1][3][1]&A11=1&A 12=1 bin/nl.cgi?A1=c&A2=0&A3=4&A4=[4][1][3][1]&A11=1&A 12=1

4. Present the next method by crossing out. Using manipulatives to model subtraction, Have them use their counters, connecting cubes, and beans, to model subtraction, as well as pictures to illustrate subtraction problems.

7 – 3 = 4

7 – 0 = 7 7 – 7 = 0

4. Have them more activities using manipulatives. Do the activities shows in the overhead to demonstrate subtraction using crossing out method.

5. Introduce the basic concept in subtraction. 7 = subtrahend minus - _3 = minuend 4 = difference

Definition of terms: Subtrahend It is the number where to subtract. Minuend It is the number to be subtracted. Minus Sign ( - ) It tells us that we are subtracting the numbers. Difference It is called the answer of a subtraction.

6. Individual Work: Using the show board, the pupils will answer the following activity in the power point slide below.

How many LEMONS are hiding under the SQUARE, if the total is 3 ? SQUARE

How many APPLES are hiding under the TRIANGLE if the total is 7 ? TRIANGLE

How many ORANGES are hiding under the CIRCLE if the total is 9 ? CIRCLE

How many LIMES are hiding under the DIAMOND if the total is 8 ? DIAMOND

How many RASPBERRIES are hiding under the HEXAGON if the total is 4 ? HEXAGON

Assessment 1. Use the links to answer the activity in the overhead. Number Line Hopping Activity Sheet /number-line-subtraction2.pdf

2. Draw an object using any method in subtraction. Then write the answer. 6-3= ____ = __________________ 9- 2=____ = __________________ 8-4= ____ = __________________ 5-1= ____ = __________________

Extensions Pose such puzzles as, "I am the number you land on when you a take a hop of 5 and then hop back 1. Who am I?" Have children create and share similar problems. They can write their puzzles on file cards and give the cards to students in other classes to solve.