Examples of what pupils should know and be able to do
Simplify these expressions:
- 3a + 2b + 2a – b
- 4x + 7 + 3x – 3 – x
- 3(x + 5)
- 12 – (n – 3)
- m(n – p)
- 4(a + 2b) – 2(2a + b)
- FTM(S) Y789 pp. 116-17 - Acrobat pdf document (60Kb)
- 2000 test P1 Q11 (L5) - Microsoft word document (28Kb)
- 2000 test P2 Q13 (L5) - Microsoft word document (48Kb)
- 2001 test P2 Q15 (L5) - Microsoft word document (24Kb)
Probing questions
Can you write an expression that would simplify to, e.g.
6m − 3n, or 8 (3x + 6)?
Are there others?
Can you give me an expression that is equivalent to, e.g.
4p + 3q − 2?
Are there others?
What do you look for when you have an expression to simplify? What are the important stages?
What hints and tips would you give to someone about simplifying expressions?
Removing a bracket from an expression:
Give pupils examples of multiplying out a bracket that includes errors. Ask them to identify and talk through the errors and how they should be corrected, e.g.
4(b + 2) = 4b + 2
3(p − 4) = 3p − 7
−2(5 − b) = −10 − 2b
12 − (n − 3) = 9 − n
Similarly for simplifying.
What if pupils find this a barrier?
Use classifying, matching or pyramid activities from Teaching mental mathematics from Level 5 to generate mathematical talk and expose misconceptions.
Ask pupils to write expressions in as many ways as they can, e.g.
3m can be expressed as:
m + m + m
2m + m
3 × m
etc.
Devise sets of equivalent expressions, write them on cards and ask pupils to sort them into the equivalent sets.
Use a clouding the picture approach to help pupils expand as well
as simplify expressions.
- TMM from L5 - algebra pp. 10-12 - Acrobat pdf document (76Kb)
- Booster Y9 lesson 6 (algebra expressions) - Microsoft word document (44Kb)
- T5 stingers 9 - Microsoft word document (36Kb)
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