Adding natural numbers in memory
Dodawanie pamięciowe liczb naturalnych
Learning objectives
You will learn the properties of addition and you will learn different methods of addition of two‑digit natural numbers in memory.
Learning effect
You add two‑digit natural numbers in memory.
Introduction:
Think about how to add natural numbers. Try to recall what the numbers that we add and the resultresult of adding are called.
Put a number in place of x, so that the equation written is true. Write down the observed property.
a) 4 + x = 4,
b) x + 5 = 5,
c) 0 + 6 = x,
d) 8 + 0 = x.
Conclusion:
- If one of the addends is equal to zero, then the sumsum equals the other addendaddend.
Conclusion:
- In addition you can easily change the order of addends and the sumsum or totaltotal is not subject to any change.
This property is called commutative additioncommutative addition.
Open slideshow and observe how we can add two numbers to each other.
After completing the exercise, present the results of your observations.
Zasób interaktywny dostępny pod adresem https://zpe.gov.pl/a/DEPHee7kP
Open the slideshow and observe the properties of addition.
Zasób interaktywny dostępny pod adresem https://zpe.gov.pl/a/DEPHee7kP
Conclusion:
- By adding several numbers, you can combine two addends freely, and the sumsum will not change, e.g. (2 + 3) + 4 = 2 + (3 + 4).
This addition feature is called associative property.
Conclusion:
- By adding a few numbers, you can add the addends and the totaltotal will not change,
e.g. (2 + 3) + 4 = 2 + (3 + 4).
This addition feature is called Associative property.
Analyze the addition methods given in the drawings.
Method 1.
Method 2.
Method 3.
Calculate each of the given sums using different methods.
a) 34 + 43,
b) 46 + 56,
c) 68 + 36,
d) 79 + 56,
e) 57 + 38.
Calculate the sums using the acquired skills.
a) 25 + 46 + 65 + 84,
b) 31 + 75 + 39 + 15,
c) 37 + 52 + 13 + 18.
Solve the word problem. Write down the resultresult in your notebook.
Julia collected 27 stickers, and Basia 36. How many stickers do the girls have together?
Task for volunteers:
Calculate by any method.
a) 120 + 356,
b) 254 + 657.
Do the revision exercises.
Remember:
- Adding numbers and the resultresult of adding is called sumsum, and the numbers that we add are called addends.
- If one of the addends is equal to zero, then the sumsum equals the other addendaddend.
- In addition, you can change the order of addends, and the sumsum will not change, e.g. 2 + 3 = 3 + 2. We say that adding has a commutative property .
- By adding a few numbers, you can combine the addends as you like, and the sumsum will not change, e.g. (2 + 3) + 4 = 2 + (3 + 4). We say adding has associative property.
Exercises
Indicate the correct result, remembering that you can change the order of addends and combine them accordingly 26+27+28+29+30+31+32+33+34.
- 274
- 270
- 264
- 266
Tomek had 56 PLN in his moneybox. His grandfather added 30 PLN to his money box, and Tomek’s aunt another 15 PLN. How much money is in the moneybox now?
Create a word problem which can be solved using an expression:
217 + 115.
Write the word problem in English.
Indicate which pairs of expressions or words are translated correctly.
- przemienność dodawania - commutative addition
- łączność dodawania - associative addition
- składnik dodawania - addend
- suma - total / sum
- dodawanie zera - result / total
- wynik dodawania - adding zero
- addend
- associative addition
- total/ sum
- suma
- łączność dodawania
- składnik dodawania
- przemienność dodawania
- commutative addition
Glossary
składnik dodawania
Nagranie dostępne na portalu epodreczniki.pl
wymowa w języku angielskim: addend
przemienność dodawania
Nagranie dostępne na portalu epodreczniki.pl
wymowa w języku angielskim: commutative addition
wynik dodawania
Nagranie dostępne na portalu epodreczniki.pl
wymowa w języku angielskim: result
suma
Nagranie dostępne na portalu epodreczniki.pl
wymowa w języku angielskim: sum
wynik dodawania
Nagranie dostępne na portalu epodreczniki.pl
wymowa w języku angielskim: total
Keywords
commutative additioncommutative addition - in adding, a property in which you can change the order of addends, and the sum will not change