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Mathematical symbols:

• Sum = + 
• + means add
• Difference  - 
• - means subtract
• Product = x 
• x means to multiply
• Quotient = ÷ 
• ÷ means to divide

Rules for rounding off

If the digit to the right of the place you are rounding off to is less than 5, round down.

If the digit to the right of the place you are rounding off to is 5 or more, round up.

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Useful squares

Principal units:

kilo = thousand

milli - thousandth

centi - hundredth

metre - measure

Capacity:

• 1 litre = 1000 millilitres   or 1 l = 1000ml
• 1 millilitre = 0,001 litre   or  1 ml = 0,001 l 
• 1 kiloliter = 1000 litres    or  1 kl  = 1000 l
• 1 litre  =  0,001 kiloliter   or  1 l = 0,001  kl

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Percentages:

100 % = 1 whole

75 % =  

50 % =

25%  =

10%  =

5 %  =

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Formulas:

To calculate:

Area of a rectangle:        A = lw                      l=length , w = width (breadth)

Area of a square:            A = l x l                     l = length

Area of a triangle:          A = 1/2 b x h           b=base, h= height

Volume of a cuboid:      V= lbh                      l= length,    b= breadth,         h=height

Volume of a cube:          V = lxlxl                   l  = length