Maths Prelims

Direct Variation

• As one value goes up ⬆, the other value goes up ⬆

• As one value goes down ⬇, the other value goes down ⬇

Inverse Variation

• As one value goes up ⬆, the other value goes down ⬇

• the other value goes down⬇, the other value goes up ⬆

metres squared to hectares

converting units of length

converting mass

converting capacity

converting time

Difference between latitudes (North & South)

Same - minus

Different - add

Finding coordinates (NSEW)

same - add

different - minus

World Time Differences

Angular difference (Difference of Longitude)

Same - minus

different - add

Random sample

Based on choosing members of the population by chance

Stratified sample

Involves selection of people in various categories in the same proportion as they occur over the whole population

Systematic sample

The people are chosen in an organised matter

numerical discrete

number of children

(counted items)

numerical continuous

(measured characteristics)

weight

Area of square

s²

area of rectangle

l x w

area of triangle

½ x b x h

area of a circle

πr²

area of parallelogram

b x h

area or trapezoid

½ (a + b) h

area of sector

θ/360 x πr²

surface area and volume of cube

V = s³

SA = 6s²

surface area and volume of rectangular prism

V = l x w x h

SA = 2(lw + lh + wh)

surface area and volume of triangular prism

V = A triangle x h

SA = 2Atriange + Ptruanglw)

surface area and volume of cylinder

V = pier²h

SA = 2pier² + 2pierh

volume and surface area of square pyramid

volume and surface area of a cone

volume and surface area of sphere

capacity

1cm³ = 1mL

1000cm³ = 1000mL = 1L

1m³ = 1000L