ALGEBRA: Open Sentence and Algebraic Sentence

LESSON 4

ALGEBRA: Use of Letters in Mathematics

OPEN SENTENCE AND ALGEBRAIC SENTENCE

Open sentence is a mathematical statement in which numbers and boxes (SPACE) are used. The boxes (SPACE) represent the unknown quantities (amounts).

Algebraic sentence is a mathematical statement written with a combination of letters and numbers. The letters represent the unknown quantities (amounts).

Open sentence can be changed into algebraic sentence. Let’s learn how!

EXAMPLE 1

Turn the open sentence into algebraic sentence 3 + [ ] = 10 

SOLUTION

3 + [ ] = 10

The box (SPACE) in open sentence represents unknown number. Unknown numbers are represented by letters in algebraic sentence.

Let’s use letter a to represent the unknown number. Then the algebraic sentence can be written as

3 + a = 10

EXAMPLE 2

Turn the open sentence into algebraic sentence [ ] - 2 = 5

SOLUTION

[ ] - 2 = 5

Let’s use letter b to represent the unknown number. The algebraic sentence is

b - 2 = 5

EXAMPLE 3

Turn the open sentence into algebraic sentence 4 + 2 = [ ]

SOLUTION

4 + 2 = [ ]

Let’s use letter c to represent the unknown number. The algebraic sentence is

4 + 2 = c

PUSH IT IN!

Go over the examples again. Write the open sentences down in your note pad and attempt writing them as algebraic sentence without looking at the examples.

 Did you get them? 

Yes? Good! Now go to the activity.

No? Good. There are some little misunderstandings here. Let’s solve it together. Send me a COMMENT!

ACTIVITY

Turn each open sentence below into algebraic sentence.

1. 9 + 5 = [ ]
2. [ ] = 6 + 3
3. 7 - [ ] = 3
4. [ ] - 5 = 7
5. [ ] + 4 = 9

    

Post the solution as a COMMENT to this lesson. Include your name or nickname and email because every COMMENTS will be replied. I’m expecting your COMMENT.

Congratulation! You've completed this lesson. Now let's go to LESSON 5: MATHEMATICAL OPERATIONS WITH ALGEBRAIC TERMS.