Thinking Skills
The Odd One Out Algebra Challenge!
A.
y=x2+5x+6
B.
E.
F.
D.
(x+1)(x+5)
G.
J.
H.
M.
N.
y=x(x+2)(x+3)
y=x+2
(x+1)2
y=x2+x+2
L.
y=(x-0.5)2+1.75
K.
√x
y=5
O.
P.
x=-2
Q.
y=x2+6x+5
R.
U.
(x+2)(x+3)
V.
y=(x+7)2-50
y=1+2
x
S.
x-1
x3/x2
x=-3
y=x2+2x+1
8x+4
I.
C.
x=3
T.
y=(x-3)2-4
W.
y=4
X.
y=x1/2
x2+14x-1
Complete the following tasks, using the Grid above.
1. a) Using the squares labelled A K Q F. explain which one is the Odd One Out.
b) What do AKQF. all have in common?
2. Which of the following is the Odd One Out? Give reasons for your answers.
MOGA
3. Using the squares labelled RODJ. explain which one is the Odd One Out.
4. Explain the relationship between each of the following - SPQT.
5. Create 5 of your own sets of four squares and explain which the Odd One Out from
your set is, or explain the relationship between each expression in your set.
6. Which boxes from the grid are connected by x = -2
Show the proof / explanation where ever possible.
7. Which expressions would equal 12 if x = 1?
Thinking Skills
As a precursor to this activity it would be a good idea to review the target language of Algebra
especially…
Factor, Factorisation, Substitution, Solve, Solution, Expand, Equation, Expression,
Terms, Coefficient
Pupils should present their odd one out answers showing clear working out and use of
appropriate language whenever possible.
Potential Answer sheet:
1. F
2(x – 3)
H
2x + 6
O
4x – 12
2
R 2x - 6
a) Some possible explanations:
F
is in Brackets
H
has the wrong sign so is the only one that gives a different outcome.
R
is expanded.
O
is divided
b) they all have a coefficient of 2
2. I 7x + 1 = 50
U Solve
X x=7
P 3x – 5 = 16
Some possible explanations:
I
Is the only one that could have been written with a power e.g. 7 ² + 1 = 50
U
Odd because it is the only word
X
7 gives the value of x. It is not an equation I & P are and Solve is what you do with an
equation.
P
The only one that involves subtraction
3. N xy(3x + 15y) K 3xy(x + 5y) W 3x²y + 15xy²
T Factor
Some possible explanations:
N
Incorrectly factorised
K
Only one expressed correctly in Brackets
W
Only expanded expression
T
Odd because it is the only word
4. L
x = -7
Q x² = 49
L& X are both valid values of x for Q&V
None of them have coefficients
5. B C G A E M S
V x² + 4 = 53
X x=7