Unit 9: Expressions and formulae

​Unit 9: Expressions and formulae

Activity 1: Construct expressions

Multiple Choice

Nine less than the product of a number and 4

• 9 - (n + 4)

• 9/4n

• 9 - 4n

• 4n - 9

Multiple Choice

Seven more than the quotient of ten and a number

• 7 + 10/n

• (7 + n) ÷ 10

• 7 + n/10

• 7n/10

Multiple Choice

Eight less than the product of a number and five

• 8 - (e + 5)

• 5e - 8

• 8 - 5e

• 5(8 - e)

Multiple Choice

Ten times a number that is 5 less than x

• 10 (5 - x)

• 10(x - 5)

• 10x - 5

• 10 × 5 - x

Multiple Choice

An orange cost y dollars and an apple costs x dollars.  

Write an expression for 3 apples and 2 oranges.  

• 2x+3y

• 5xy

• 3y+2x

• 3x+2y

Multiple Choice

An electrician charges a £30 to come to your house plus £20 an hour. What formula works out the cost C for n hours of work?

• C = 20 + 30n

• C = 30 + 20n

• C = 50n

• C = 50 + n

Activity 2: Substitution​

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Multiple Choice

10 less than a number, k

• k - 10

• 10 ÷ k

• 10/k

• 10-k

Multiple Choice

If x = 5, find the value of 7x-1.

• 34

• 36

• 35

• 37

Multiple Choice

Half a number, y

• 2y

• y/2

• y + 1/2

• y - 1/2

Multiple Choice

If y = 4, find the value of 3y+5.

• 27

• 12

• 17

• 18

Multiple Choice

A number decreased by 39

• x - 39

• 39 - x

• x ÷ 39

• x + 39

Multiple Choice

If y = 7, find the value of 2(y+4).

• 11

• 22

• 20

• 12

Multiple Choice

Ten more than twice a number

• 10 + m/2

• 2 × 10 + m

• 2m + 10

• 10m + 2

Multiple Choice

If a = 6 and b = 7,find the value of 15-a-b.

• 2
• 3
• 4
• 5

Multiple Choice

Three times the difference of a number and 7

• 3(7 - y)

• 3y - 7

• 3(y - 7)

• 3(y + 7)

Multiple Choice

If p = 3 and q = 5, find p + q + 2

• 12

• 10

• 8

• 11

Multiple Choice

What is the value of -3y - 9 if y = -8?

• 15

• -15

• 14

• -14

Multiple Choice

If a = 4 and b = 6, what is the value of 3a + 5b?

• 40

• 42

• 44

• 46

Multiple Choice

What is the value of -6s - 5h if s = 9 and h = 5?

• -79

• 79

• 78

• -78

Activity 3: Order of operations​

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Multiple Choice

_{18 + 2 x 4}

• 80

• 26

• 24

• 13

Multiple Choice

3(9²)

• 243

• 25

• 126

• 54

Multiple Choice

34 + [ 16 - (8-3)]

•  34

• 29 

• 45

• 28

Multiple Choice

2² + 3 x 4 − 12

• 16

• 4

• 8

• 129

Multiple Choice

(7-4)² + (20-19) - 10

• -3

• 57

• 0

• 1

Multiple Choice

8 ÷ 8 + 6 × 2

• 8

• 13

• 14

• 23

Multiple Choice

Expand the following expression...

• 21x - 14

• 14x - 21

• 21x - 5

• 14x - 5

Multiple Choice

Factorise 4x+12

• 4(x+3)

• 4(x+12)

Multiple Choice

Expand the following expression...

• 5x + 20

• 20x + 5

• 5x + 9

• 5x + 4

Multiple Choice

Find HCF of 5kt² and 3k³t

• 15kt
• kt
• 15k³t²
• k³t²

Multiple Choice

Factorise 6x+4

• 2(x+4)
• 2(3x+2)