Substitution on the farm.
Mr Johnson
Farm song
http://www.youtube.com/watch?v=fJyfh-9b8ZA
http://www.youtube.com/watch?v=w6ySjiDl6-4
CODEWORDS.
If this is the code…
A=1, B=2, C=3, etc.
What does this say? 9 12,15,22,5 8,1,19,8,18
Can you make up your own code and write
a sentence for person next to you to solve?
Ploughing and Sowing.
Farmer Fred wants to plough his field?
So what information
do we need?
So we need to know…
• The size of the field.
• The size of the plough.
• The speed of the tractor
with the plough.
• Labour cost.
• Fuel cost.
2
4
3
1
2
4
1
3
Tractor Price (a) kpl (c )
kph with plough (d)
kph with seed drill (e)
1
£12,000
12
8
6
2
£25,000
9
5
5
3
£100,000
15
11
5
4
£1,500
8
8
5
Plough
Price (f) Width (h)
1
£15,000
10m
2
£3,000
5m
3
£2,500
3m
4
£8,000
6m
Labour cost (i) = £15 per hour
Size of field ( x by y) = 150m by 300m
Red diesel per litre (j) = £0.85
What now?
• Choose a tractor and plough.
• Calculate the cost of ploughing the field using your
chosen tractor.
• Present your findings clearly of the A3 sheet.
• Prepare a presentation so that you can share you
results with the class.
Extension.
Can you find the best combination
of tractor and plough?
So what have we learnt?
Letters can be used to
represent variables.
On your Mini Whiteboards…
1.If x = 2 what is x + 2?
2.If y = 3 what is y – 2?
3.If p = 38 and q = 17 what is p + q?
4.If r = 12 and z = 27 what is r – z?
5.If s = 15, t = 2 and x = 5 what is s + t – x ?
NC level 5A
On your Mini Whiteboards…
IF X=1, Y=2, Z=7, R=12, S=25
1. 2X =
2. 3R =
3. 2R + 5Z =
4. 3Z + 2Y – 2X =
On you Mini Whiteboards…
If X=3, Y=6, Z=12, R=25, S=5 solve these...
Now try these in your books…