This is a level 2 algebra strand activity from the Figure It Out series.

A PDF of the student activity is included.

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solve basic facts

select operation symbols ( +, -, x, ÷) to complete an equation

FIO, Level 2-3, Algebra, Crunch Machine, page 17

classmate

#### Activity One

Organising the results in an in/out table may help students to recognise patterns:

Activity Two

Some students may need a calculator to help them, although processing the problems mentally is more efficient.

Realising that the = sign must go in one of the vacant squares is a clue to how the problems can be

solved in an organised way.

For example, question 3 offers three possibilities:

15 = 21 4 40 [This looks unlikely.]

15 21 = 4 40 [More likely, although + and – are the only likely operators.]

15 21 4 = 40 [Using addition signs gives the correct solution.]

Students may enjoy making up their own problems, although this is another case where creating

problems is much easier than solving them.

#### Answers to Activities

**Activity One**

+ 5

2 + 5 = 7

4 + 5 = 9

6 + 5 = 11

8 + 5 = 13

10 + 5 = 15

- 8

8 – 8 = 0

12 – 8 = 4

16 – 8 = 8

20 – 8 = 12

x 3

7 x 3 = 21

8 x 3 = 24

9 x 3 = 27

10 x 3 = 30

÷ 5

5 ÷ 5 = 1

10 ÷ 5 = 2

15 ÷ 5 = 3

20 ÷ 5 = 4**Activity Two**

1. 6 ÷ 3 = 2 or 6 = 3 x 2

2. 50 = 10 + 10 + 30, 50 – 10 = 10 + 30, or 50 – 10 – 10 = 30

3. 15 + 21 + 4 = 40

4. 24 = 6 x 4 or 24 ÷ 6 = 4

5. 16 + 17 = 3 x 11

6. 10 = 2 x 3 + 4 or 10 + 2 = 3 x 4

7. 12 = 3 x 2 x 2 or 12 ÷ 3 = 2 x 2

8. 40 + 3 + 7 = 50

**Activity Three**

Answers will vary.