 # Simple Algebraic Substitution with Negative Numbers

In this worksheet, students substitute negative numbers for letters and work out the value of simple expressions with one variable. Key stage:  KS 2

Curriculum topic:   Maths and Numerical Reasoning

Curriculum subtopic:   Equations and Algebra

Difficulty level:   ### QUESTION 1 of 10

When we substitute a number for a letter, we simply replace the letter with the number.

However, we must remember that 4b means 4 x b.

Example

Work out the value of the following expression when a = -4

3a - 7

3a - 7

= (3 x a) - 7

= (3 x - 4) - 7

= -12 - 7

= -19

Work out the value of the following expression when a = -7

20 - a

Work out the value of the following expression when a = -7

20 + 2a

Work out the value of the following expression when a = -10

20 + 2a

Work out the value of the following expression when a = -10

a + a

Work out the value of the following expression when a = -3

5a + 2

Work out the value of the following expression when a = -8

2 - 2a

Work out the value of the following expression when a = -4

10 - 2a

Work out the value of the following expression when a = -4

2a + 5

Work out the value of the following expression when a = -7

2a + 6

Work out the value of the following expression when a = -9

2a - 7

• Question 1

Work out the value of the following expression when a = -7

20 - a

27
EDDIE SAYS
20 - a 20 - (-7) 20 + 7 27
• Question 2

Work out the value of the following expression when a = -7

20 + 2a

6
EDDIE SAYS
20 + 2a 20 + (2 x a) 20 + (2 x -7) 20 + (- 14) 20 - 14 6
• Question 3

Work out the value of the following expression when a = -10

20 + 2a

0
EDDIE SAYS
20 + 2a 20 + (2 x a) 20 + (2 x -10) 20 + (-20) 20 - 20 0
• Question 4

Work out the value of the following expression when a = -10

a + a

-20
EDDIE SAYS
a + a (-10) + (-10) -10 - 10 -20
• Question 5

Work out the value of the following expression when a = -3

5a + 2

-13
EDDIE SAYS
5a + 2 (5 x a) + 2 (5 x -3) + 2 -15 + 2 -13
• Question 6

Work out the value of the following expression when a = -8

2 - 2a

18
EDDIE SAYS
2 - 2a 2 - (2 x a) 2 - (2 x -8) 2 - (-16) 2 + 16 18
• Question 7

Work out the value of the following expression when a = -4

10 - 2a

18
EDDIE SAYS
10 - 2a 10 - (2 x a) 10 - (2 x -4) 10 - (-8) 10 + 8 18
• Question 8

Work out the value of the following expression when a = -4

2a + 5

-3
EDDIE SAYS
2a + 5 (2 x a) + 5 (2 x -4) + 5 (-8) + 5 -3
• Question 9

Work out the value of the following expression when a = -7

2a + 6

-8
EDDIE SAYS
2a + 6 (2 x a) + 6 (2 x -7) + 6 (-14) + 6 -8
• Question 10

Work out the value of the following expression when a = -9

2a - 7

-25
EDDIE SAYS
2a - 7 (2 x a) - 7 (2 x -9) - 7 (-18) - 7 -25
---- OR ----

Sign up for a £1 trial so you can track and measure your child's progress on this activity.

### What is EdPlace?

We're your National Curriculum aligned online education content provider helping each child succeed in English, maths and science from year 1 to GCSE. With an EdPlace account you’ll be able to track and measure progress, helping each child achieve their best. We build confidence and attainment by personalising each child’s learning at a level that suits them.

Get started 