Making expressions and gathering terms

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Making expressions and gathering terms
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Sweets
s number of sweets in the box
If I add 2 how many? s 2 If I add 4 more,
how many? s 2 4 s 6 If I then eat 10,
how many? s 6 10 s 4 How many in 2
boxes? s s 2 x s 2s How many in 11
boxes? 11 x s 11s How many in 3 boxes, then
I eat 7? 3s -7
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Algebra - the basics Collecting Like Terms
h number of biscuits in a packet of HobNobs r
number of biscuits in a packet of Rich Tea
6 lots of h 6 x h 6h
r
4 x r 4r
4
4h
3r
h 2r
h 2r 3h r 4h 3r
3h r
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How many biscuits if - 20 in a pack of
Hobnobs - 25 in a pack of Rich Tea? h 20 r
25 B 4 x 20 3 x 25 80 75
155 Biscuits Yum Yum
B 4h 3r
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Algebra - the basics Collecting Like Terms -
with loose biscuits
3h 2r 5
h 2r 3
Altogether
3h 2r 5 h 2r 3 4h 4r 8
Gather number separately
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1.
8
2h 2r
5h
7h 2r
5h 5r
8a 10b
12h 4r 4
3x 4y
12x 6y 4
19a 5b -4
8a 10b
6h 3r 10
14h - 13r
11x 4y
2x 11y 2z
14a - 12b 3
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Algebra - the basics Working With Powers
w
Area w x w
w2
w
w4
w x w x w x w
The power tells us how many are multiplied
together
a8
a x a x a x a x a x a x a x a
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Algebra - the basics Products
Pg.153 ex 82 and 83
Recall, 4h 4 x h
Similarly, gh g x h
When letters are multiplied together, in algebra,
you dont need to put the multiplication (x) sign
Note always write the number first, then the
letters in alphabetical order
E.g. f x g fg g x 3h g x 3 x h 3gh 4r x 2s
4 x r x 2 x s 8rs (2p)2 2p x 2p 2 x p x 2
x p 4p2
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Algebra - Brackets
b 5
b 5 b 5
b 5
3 (b 5)
3 lots of a tin of biscuits and 5 loose ones
b 5 b 5 b 5 3b
15 b
b b 5 5 5
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Algebra - Brackets
h 2r 3 h 2r 3
h 2r 3
3 (h 2r 3)
h 2r 3 h 2r 3 h 2r 3 h
h h 2r 2r 2r 3 3 3 3h 6r 9
3h
6r
9
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Algebra - Brackets
3(4x - 6)
3 times 4x - 3 times 6 3 x 4x -
3 x 6 12x - 18
Everything inside the bracket must be multiplied
by the number outside
Pg.155-156 ex 85 and 86
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Algebra - Brackets
m(4n - 6)
m times 4n - m times 6 m x 4n -
m x 6 4mn 6m
Everything inside the bracket must be multiplied
by the number outside
Pg.155-156 ex 85 and 86
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Algebra - Brackets
3(4x - 6) 4(x 1)
(3 x 4x - 3 x 6) (4 x x 4 x 1) (12x
18) (4x -4) 12x 18 -4x - -4 -- equals
12x 18 4x 4 Gather like terms 8x
- 14
Everything inside the bracket must be multiplied
by the number outside
Pg.155-156 ex 85 and 86