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## JSS1: MATHEMATICS - 2ND TERM

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#### Quizzes

Lesson 1, Topic 1
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# Using Shapes to Represent Numbers

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### Open Sentences:

Algebra is the branch of mathematics in which letters and other general symbols are used to represent numbers and quantities in formulae and equations.

We say that $$\scriptsize 15 \: + \: \boxed{?} = 20$$ is an open sentence. We can put any value in the box but usually, only one value will make the open sentence true.

$$\scriptsize 15 \: + \: \boxed{?} = 20$$ will be true if 5 goes in the box

$$\scriptsize 15 \: + \: \boxed{5} = 20 \: is \: true$$

### Example 1

Check the following mathematical statements carefully;

### Example 2

Find the missing numbers that make the following open sentences true:

i. $$\;\;\scriptsize \boxed{?} + 7 = 14 \\ \rightarrow \scriptsize \boxed{7} + 7 = 14$$

ii. $$\;\;\scriptsize 12 + \boxed{?} = 18 \\\rightarrow \scriptsize 12 + \boxed{6} = 18$$

iii. $$\;\; \scriptsize 14 + 7 = \boxed{?} \\ \rightarrow \scriptsize 14 + 7 = \boxed{21}$$

iv. $$\;\;\scriptsize \boxed{?} \: – \: 15 = 0 \\ \rightarrow \scriptsize \boxed{15} \: – \: 15 = 0$$

v. $$\;\; \scriptsize 12 \: \times \: \boxed{?} = 36 \\ \rightarrow \scriptsize \scriptsize 12 \: \times \: \boxed{3} = 36$$

vi. $$\;\; \scriptsize \boxed{?} \: \times \: 5 = 40 \\ \rightarrow \scriptsize \boxed{8} \: \times \: 5 = 40$$

vii. $$\;\; \scriptsize12 \: \div \: \boxed{?} = 3 \\ \rightarrow \scriptsize12 \; \div \: \boxed{4} = 3$$

viii. $$\;\; \scriptsize (5 \: \times \: 8) \: – \: 5 = \boxed{?} \\ \rightarrow \scriptsize 40 \: – \: 5 = \boxed{35}$$

Remember BODMAS. We solve the bracket first before we subtract.