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# THE USE OF SYMBOLS

CONTENT

1. Open Sentences
2. Letters to Represent Symbols or the Unknown
3. Open Sentences with Two Unknowns

## Open Sentences

Consider the question:

“What number added to $$7$$ will give you $$12$$ ?” How will you write that as a mathematical sentence?

A mathematical sentence consists of numbers and symbols (that represent unknown numbers) called variables. The equivalent mathematical sentence of the above question can be written as:
$$\text{ }+ 7 = 12$$

We call the above equation an open sentence.

Example:

$$14 +\text{ }$$        $$= 17$$

This will be true if $$3$$ goes in the box.

$$14 +\text{ }$$    $$3$$  $$= 17$$

We say $$14 +\text{ }$$        $$= 17$$ is an open sentence. Any value can go in the box but usually, only one value will make an open sentence true.

CLASS ACTIVITY

In each sentence, find the number which makes it true.

Lesson tags: JSS1 Mathematics, JSS1 Mathematics Evaluation Questions, JSS1 Mathematics Evaluation Questions Second Term, JSS1 Mathematics Objective Questions, JSS1 Mathematics Objective Questions Second Term, JSS1 Mathematics Second Term, Mathematics Lesson Notes, Mathematics Objective Questions
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