Algebra

Unknown Values & Combined Operations

1

Find the Missing Number (Addition)

Write the number that makes each equation true.

___ + 15 = 27

___ + 34 = 50

23 + ___ = 41

___ + 48 = 75

2

Find the Missing Number (Subtraction)

Write the number that makes each equation true.

36 − ___ = 19

50 − ___ = 28

___ − 14 = 33

72 − ___ = 45

3

Find the Missing Number (Multiplication)

Write the number that makes each equation true.

___ × 6 = 42

___ × 8 = 56

9 × ___ = 63

___ × 12 = 84

4

Find the Missing Number (Division)

Write the number that makes each equation true.

56 ÷ ___ = 8

___ ÷ 5 = 9

72 ÷ ___ = 6

___ ÷ 7 = 11

5

Pick the Missing Number

Circle the value that makes each equation true.

___ + 18 = 35

13
17
23

42 − ___ = 15

27
33
57

___ × 7 = 49

6
7
8

60 ÷ ___ = 12

4
5
6
6

Match Equations to Unknowns

Draw a line to match each equation to the value of the unknown.

___ + 8 = 23
45 − ___ = 28
___ × 9 = 72
63 ÷ ___ = 7
9
15
8
17
7

More Equation Matching

Draw a line to match each equation to its answer.

___ + 25 = 40
80 − ___ = 55
___ × 4 = 52
96 ÷ ___ = 8
12
15
25
13
8

Write the Equation

Write an equation for each word problem, using ___ for the unknown. Then solve it.

I think of a number and add 12. The answer is 31. Equation: ___. The number is ___.

I think of a number and multiply by 5. The answer is 45. Equation: ___. The number is ___.

I think of a number and subtract 18. The answer is 24. Equation: ___. The number is ___.

9

Two-Step Equations

Find the unknown value. Work backwards! Example: 3 × ___ + 5 = 20 → 3 × ___ = 15 → ___ = 5.

4 × ___ + 3 = 19. The unknown is ___.

5 × ___ − 7 = 18. The unknown is ___.

2 × ___ + 10 = 24. The unknown is ___.

6 × ___ − 4 = 32. The unknown is ___.

10

More Two-Step Equations

Find the unknown value. Show your working.

3 × ___ + 8 = 29. The unknown is ___.

___ × 7 − 10 = 25. The unknown is ___.

8 × ___ + 6 = 46. The unknown is ___.

___ ÷ 4 + 3 = 8. The unknown is ___.

11

Which Value Makes It True?

Circle the value that makes the equation true.

3 × ___ + 2 = 14

3
4
5

24 ÷ ___ − 1 = 5

3
4
6

___ × 7 − 3 = 25

3
4
5

5 × ___ + 8 = 33

4
5
6
12

More Two-Step Choices

Circle the value that makes the equation true.

2 × ___ + 9 = 21

5
6
7

___ × 8 − 12 = 20

3
4
5

10 × ___ + 5 = 75

6
7
8

36 ÷ ___ + 2 = 8

4
6
9
13

Two-Step Word Problems

Write an equation and solve each problem.

I think of a number, double it and add 7. The answer is 23. What is the number?

I think of a number, multiply by 5 and subtract 3. The answer is 32. What is the number?

I think of a number, divide by 3 and add 4. The answer is 9. What is the number?

14

Order of Operations

Calculate each expression using the correct order of operations (multiplication/division before addition/subtraction).

3 + 4 × 5 = ___

20 − 3 × 4 = ___

6 × 3 + 8 ÷ 2 = ___

15 − 2 × 3 + 4 = ___

15

More Order of Operations

Calculate each expression. Remember: brackets first, then × and ÷, then + and −.

(3 + 4) × 5 = ___

24 ÷ (8 − 2) = ___

2 × (10 + 5) − 6 = ___

(18 − 6) ÷ 3 + 7 = ___

16

Order of Operations Check

Circle the correct answer.

8 + 2 × 3 = ?

14
30
24

(8 + 2) × 3 = ?

14
30
24

12 ÷ 4 + 2 = ?

2
5
6

12 ÷ (4 + 2) = ?

2
5
6
17

Add Brackets to Make It True

Insert brackets to make each equation true.

2 + 3 × 4 = 20 (add brackets): ___

10 − 2 × 3 = 24 (add brackets): ___

6 + 8 ÷ 2 = 7 (add brackets): ___

5 × 3 + 7 = 50 (add brackets): ___

18

Challenge Equations

Find the unknown and explain your reasoning.

(2 × ___) + (3 × ___) = 25, where both blanks are the same number. The number is ___.

(___ + 3) × 4 = 28. The unknown is ___.

100 − (___ × ___) = 51, where both blanks are the same number. The number is ___.

19

Home Activity: Equation Detective

Create and solve equations at home!

  • 1Think of a number, double it, add 6. The answer is 22. What was the number? Write the equation.
  • 2Make up 3 two-step equations for a family member to solve.
  • 3Use playing cards: flip 3 cards and try to make an equation using +, −, × or ÷.
  • 4Write a word problem that involves finding an unknown value.
  • 5Create a 'guess my rule' game with a family member using input-output tables.
20

Using Pronumerals

Use a pronumeral (letter) to write each equation, then solve.

A number x plus 14 equals 29. Equation: ___. x = ___

A number n multiplied by 8 equals 72. Equation: ___. n = ___

A number y minus 17 equals 43. Equation: ___. y = ___

A number p divided by 6 equals 12. Equation: ___. p = ___

21

Evaluating Expressions

Evaluate each expression for the given value.

3x + 2, when x = 5:

17
20
25

4n − 1, when n = 7:

26
27
28

2(p + 3), when p = 4:

10
14
20

(m − 2) × 5, when m = 8:

25
30
35
22

Substitution Practice

Substitute the given value and evaluate each expression.

5x − 3, when x = 4: ___

2n + 7, when n = 9: ___

3(y − 2), when y = 6: ___

10 − 2p, when p = 3: ___

(a + 4) × 3, when a = 5: ___

23

Match Equation to Solution

Draw a line to match each equation to its solution.

2x + 5 = 17
3n − 4 = 14
y/3 + 1 = 5
4p − 7 = 13
12
5
6
6
24

Forming Algebraic Expressions

Write an algebraic expression for each description.

A number increased by 8: ___

Twice a number decreased by 5: ___

A number divided by 4, then add 3: ___

Three times the sum of a number and 2: ___

25

Solving Equations Systematically

Use inverse operations to solve each equation. Show each step.

3x + 8 = 26. Step 1: ___. Step 2: ___. x = ___

4n − 9 = 27. Step 1: ___. Step 2: ___. n = ___

2(y + 5) = 22. Step 1: ___. Step 2: ___. y = ___

26

Sort: Which Operation to Use First?

Sort each equation by the inverse operation to use first.

x + 7 = 15
3n = 21
y − 4 = 11
p/5 = 6
2x + 3 = 11
n/2 − 1 = 5
Undo Addition first
Undo Subtraction first
Undo Multiplication first
Undo Division first
27

Order of Operations Problems

Calculate using the correct order of operations (BOMDAS).

5 + 3 × 4 − 2 = ___

(7 + 3) × (8 − 5) = ___

4² + 3 × 5 − 10 = ___

48 ÷ (2 + 4) × 3 = ___

3 × (6 − 2)² + 5 = ___

28

Writing Equations from Word Problems

Write an equation and solve it.

A box holds n books. 5 boxes hold 35 books. Write and solve: ___

Ali is x years old. 3 times his age minus 4 is 20. Write and solve: ___

After spending $25, Mia has y dollars left. She now has $48. Write and solve: ___

29

True or False: Order of Operations

Circle TRUE or FALSE.

2 + 3 × 4 = 20

TRUE
FALSE

(2 + 3) × 4 = 20

TRUE
FALSE

8 ÷ 2 + 6 = 1

TRUE
FALSE

8 ÷ (2 + 6) = 1

TRUE
FALSE
30

Algebraic Number Bonds

Find the missing value in each equation.

24
8
?
36
?
12
50
23
?
100
?
37
60
45
?
31

Input-Output Tables

Complete each input-output table.

3
7
11
19
?
2
6
18
162
?
10
8
6
2
?
32

Algebraic Problem Solving

Use algebra to solve each problem.

Theo is 3 times as old as Sam. Together they are 40. How old is each? ___

The perimeter of a square is 64 cm. Use 4s = 64 to find the side length: ___

Two numbers add to 57. The larger is 9 more than the smaller. Find both: ___

33

Combined Operations with Fractions and Decimals

Solve each combined operation problem.

3.5 × ___ + 4 = 18. The unknown = ___

___ ÷ 4 − 2.5 = 5. The unknown = ___

½ × ___ + 6 = 15. The unknown = ___

34

Generalising with Algebra

Write a general algebraic rule for each pattern.

Pattern: 4, 8, 12, 16 (for n = 1, 2, 3, 4). Rule: term = ___

Pattern: 5, 8, 11, 14. Rule: term = ___

Pattern: 1, 4, 9, 16. Rule: term = ___

35

Checking Solutions

Check if each given value solves the equation. Write YES or NO and show checking.

Does x = 4 solve 3x − 2 = 10? ___

Does n = 7 solve 2n + 5 = 19? ___

Does p = 3 solve 4(p + 2) = 24? ___

36

Equations with Negative Integers

Solve each equation involving negative integers.

x + 5 = -3. x = ___

n − 4 = -7. n = ___

2p + 1 = -5. p = ___

3y − 2 = -11. y = ___

37

Unknown Values — Summary Challenge

Solve these mixed equation challenges.

Find x: 5(x − 3) + 4 = 19. x = ___

Find n: 48 ÷ n − 2 = 6. n = ___

Write your own two-step equation and solve it: ___