Download Year 8 Revision

Year 8 Revision
Each slide will have a different topic.
There will be questions and hints to
help you.
Fractions, Decimals & Percentages
Fraction
Decimal
Percentage
1
2
0.5
50%
1
4
0.25
2
5
40%
0.3
30%
Hints:
Draw out the table and fill in the missing gaps (use your book if you get stuck)
Fractions, Decimals & Percentages
Hints:
• To convert a decimal to a percentage – multiply the number by 100
• To convert a percentage to a decimal – divide the number by 100
• To convert a fraction to a percentage – Multiply the denominator number to make 100 and do the
same to the numerator e.g. ⅘ (5 x 20 = 100) (4 x 20 = 80) = 80/100 =80%
• To convert a percentage to a fraction – put it over 100 e.g. 25% = 25/100 (don’t forget to simplify)
• To convert a fraction to a decimal – divide the denominator by the numerator
• To convert a fraction to a decimal – put it over 100 e.g. 0.7 = 70/100 or 7/10
Hints:
Write BIDMAS down when
you do the question so you
don’t forget!
HCF and LCM
Find the Highest Common
Factor of these numbers:
• 18 and 30
• 15 and 20
• 16 and 24
• 12 and 36
• 20 and 30
• 28 and 70
Hints:
Write out the factors in both (in pairs)
18 = 1 & 18, 2 & 9, 3 & 6
30 = 1 & 30, 2 & 15, 3 & 10, 5 & 6
• Circle the highest number that is in
both
Find the Lowest Common multiple
of these numbers
• 6 and 7
• 4 and 6
• 5 and 8
• 10 and 4
• 16 and 5
• 14 and 21
Hints:
Write out the timestables for both
numbers
6, 12, 18, 24, 30, 36, 42
7, 14, 21, 28, 35, 42
Until you find a number that is in
both
Percentage of an Amount
Remember the Percentage
20%
tree
Two lots
of 10%
50%
Half it
10%
Divide
by 10
80
100%
5%
Divide by
10 then
half it
15%
Add 10%
& 5%
25%
Half it &
Half it
again
75%
Add 50%
& 25%
Find the following:
Area & Perimeter
Area = L x W
9cm
Perimeter = the distance
around the outside
12cm
2cm
5cm
9cm
Hints:
Don’t forget to write your
answer in units2
e.g. 24cm2
5cm
4cm
Hints: Add up all the sides (even the
missing sides!)
Hints:
Area of a triangle =
½ base x (vertical) height
• Don’t be fooled into using the
diagonal height
Hints:
Angles in a triangle = 180°
• Use your calculator
• 180 – The other numbers inside
the triangle
Angles
Hints:
• Angles on a straight line = 180°
• Angles around a point (Circle) = 360°