Some simple rules for performing arithmetical operations:

9:54 AM arimatika, berhitung cepat, matematika, pembagian, pengurangan, penjumlahan, perkalian No Comments

• If an expression contain brackets, simplify the expression within the brackets first.
• For example:3 + (5 – 3) = 3 + 2 = 5
• If an expression contains more than one pair of brackets, that is, there are brackets within brackets, simplify the expression within the innermost pair of brackets first.
• For example: 3 [15 – (3 + 4)] = 3 + [15 – 7] = 3 + 8 = 11
  
• If an expression contains only additions and subtractions, work from left to right.
• For example: 28 + 12 – 19 = 40 – 19 = 31
• If an expression contains only multiplications and divisions, work from left to right.
• For example: 125 : 5 x 15 = 25 x 15 = 375
• If an expression contains all the four operations (i.e.) addition, subtraction, multiplication and division), do multiplication or division before addition or subtraction.
• For example: 12 + 3 x 4 – 5 : 17 = 12 + 12 – 5 = 24 – 5 = 19
  
  source: (shinglee, mathematics 1 : 14-15)
  

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