Through varied activities, the Grade 1 students are expected to do the following with at least 80% accuracy:
a. subtract numbers using the steps
b. solve problems using the steps
c. subtract two-digit numbers by two-digits subtrahend with regrouping
II. Subject Matter
Concepts: Subtraction with Regrouping
Skill Focus: Subtracting Numbers
Value Integration: Honesty
References: Realistic Math 1 by Allyn Chua-Go Tian pages 158-167.
Mathematics in a Challenging World 1 by Florinda V. Angeles pages 153-157.
Mathematics for global Challenges 1 by Luzviminda C. Funa, et.al. pages 123-128.
III. Learning Procedure
A. Engagement
Jared and Joshua decided to harvest lanzones in the farm to sell it in the market. They brought with them one big basket for their harvested lanzones. After three hours, they got tired and stopped harvesting. They counted the lanzones that they got.
95 lanzones.Jared and Joshua harvested 95 lanzones.They immediately went home. However, their brothers and sisters asked for some lanzones. So, they gave them 48 lanzones in all.
They started counting.
48 lanzones. Jard and Joshua gave 48 lanzones to their brothers and sisters.
After counting, Jared and Joshua got tired. They need some help to find out how many lanzones were left.
Can we help them?
B. Engagement
How many lanzones were given? (48)So, how many were left?
9 5
- 4 8
________
4 7
So, there are 47 lanzones left harvested by Jared and Joshua.C. Explanation
How did you get the answer of how many lanzones left harvested by Jared and Joshua?
(by subtracting the two numbers)
Let us find out how we subtract it.
How many lanzones did Jared and Joshua had harvested?How many were given to their brothers and sisters?
95 -harvested
-
48 -given
_________________
Let us subtract them following the steps.
We cannot subtract 8 from 5. 9 5
Regroup one tens from 9 tens. -
Add 1 tens and 5 ones. 4 8
10 + 5 = 15 __________
4 7
Write 8 in place of 9. 9 5
Now subtract the ones. -
15 - 8 = 7 4 8
_____________
4 7
Write 7 under the ones column.
Then subtract the tens.
8 - 4 = 4
Write 4 in the tens column.
So, how many lanzones were left? (47)
How did we subtract it? (We subtract it by regrouping one tens from the tens place. Then, subtract the ones and the tens place.
Which digit should we always start when we are going to subtract numbers? (Subtract the ones-digits first, then the tens. regroup when needed.)
Ok. I have here another problem.
Last Sunday, my mother bought 52 cupcakes.There were only 16 cupcakes left.How many cupcake were left?
Let us subtract the cupcakes bought and the cupcakes left.
5 2
-
1 6
___________
3 6
How many cupcakes left? (36)
What is the symbol in subtracting numbers? (-)
What is the first step in subtracting numbers with regrouping? ( Subtract the ones digits first then the tens place.Regrouping is done by borrowing 1 ten from the tens digit of the minuend aqnd adding this to the ones digit of the minuend.)
D. Elaborate
I have here flashcards. I will give you tag boards where you will solve the problem and show your solution. You will raise your tag boards when I say "GO". I will give you 2 minutes to solve.
Find the difference.
1.) 5 7 2.) 6 3 3.) 4 8 4.) 5 5 5.) 6 1
- 28 - 4 8 - 2 9 - 2 6 - 4 7
______ _______ _______ _______ _______
Individual Activity.
Answer Skill Builders
E. Evaluation
Directions: Subtract.
1.) 4 4 2.) 3 2 3.) 7 1 4.) 8 5 5.) 9 3
- 2 8 - 1 7 - 2 7 - 4 9 - 2 7
______ _______ _______ ______ _______
6.) 9 1 7.) 8 3 8.) 7 5 9.) 8 4 10.) 6 2
- 2 8 - 4 7 - 3 9 - 3 9 - 3 8
______ ______ _______ ________ _________
IV. Assignment
Directions: Find the difference of the following.
1.) 7 4 2.) 7 6 3.) 8 8 4.) 6 4 5.) 5 3
- 5 8 - 5 9 - 5 9 - 4 8 - 4 6
______ _______ _______ _______ _______
