Maths - Number

Maths - Number

1. Square, cube, triangle and prime numbers

   • Xsquared = X*X
   • Xcubed = X*X*X
   • Triangle number = 1+2, 1+2+3 ect.
   • Prime number = only two factors

2. Factor Trees

   • Venn Diagram
     • HCF = Product of overlapping numbers
     • LCM = Product of all numbers
   • Product of prime factors e.g. 2sqaured * 3cubed

3. Percent, fraction and decimal

   • 23/100 = 0.23 = 23%
   • 0.1 rec = 1/9 0.12 rec = 12/99

4. Fractions

   • Adding and subtracting - Find common denominator, Add/subtract numerators
   • Multiplying - Multiply numerator and donominator
   • Divide - Skip flip and multiply

5. Ratio

   • 50 to 1:4 = 10:40

6. Percentage increase/deacrease

   • Per inc - 1+per inc
   • Per dec - 1-per dec

7. Surds

   • Treat like algebra
   • 1/root2
     • *root2
       • root2/2

8. Bounds

   • Upper bound of 21 (2s.f) =21.5
   • Lower bound of 21 (2 s.f) = 20.5
   • UB = UB+UB UB*UB UB-LB UB/LB
   • LB = LB+LB LB*LB LB-UB LB/UB

9. Reciprocals

   • Flip fraction upside down

10. Compound interest

    • X.* (IR+1)to the power of years of interest

11. Proportion

    • Direct Y=kx
    • Indirect Y = k/x

12. Rules of indices

    • Negative indices - Power of denominator - reciprocal
    • Fraction - root denominator to the power of numerator