Maths (Number + Basic Algebra)

Maths (Number + Basic Algebra)

1. Set theory

   • a collection of distinct entities regarded as a unit, being either individually specified or (more usually) satisfying specified conditions
   • Terms and Symbols
     • A ∩ B (Intersection)
       • the new set that contains every element that is in both of the input sets
     • A ∪ B (Union)
       • the new set that contains every element from either of A and B
     • ~A (Not A)
       • the new set gets everything that is in the universe but is outside of A
     • A – B (A minus B)
       • if it's in A and not in B, then it goes into the new set
     • ~(A U B) (Not A and B)
       • the new set gets everything that is outside A and B
     • ~(A n B) (Not A overlap B)
       • the new set contains everything outside of the overlap of A and B

2. Percentages

   • ‘percentage’ means ‘number of parts per 100’
   • 15% of 120 = 100 15 x 120

3. Ratio and Proportion

   • Share £416 in the ratio 4:3:1
     • 208 : 156 : 52

4. Degree of Accuracy

   • Upper and Lower Bounds
     • piece of wood is 12cm long
       • LB = 11.5cm
       • UB = 12.5cm
   • Significant Figures
     • 0.0000058763 correct to 2 significant figures
       • 0.0000059
     • 368249 correct to 1 significant figure
       • 400000

5. Standard Form

   • express numbers in the form a × 10n where n is an integer and 1 ≤ a < 10
     • 150 000 000 = 1.5 x 10^8