Year 9 Other Stuff Flashcards
How to multiply fractions?
x a ax
- × - = —–
y b by
How to divide fractions?
Keep first fraction same, change ÷ to × and take reciprocal of second fraction ‘flip it’
How to add and subtract fractions
Make it so they have a common denominator, then add together
How to write a recurring decimal as a fraction?
Line up decimals, use algebra, you know how to do this omg and if you don’t look in your book
How to work out the combined multiplier?
Multiply together the multipliers
a¹
a
a‐¹
a
a‐²
a²
What does a negative power do to a fraction
It reciprocates it
(ab)³
a³ × b³
What does a power of ½ do to a number?
It square roots it
What does a power of ⅓ do to a number?
It cube roots it
When is a number in standard form?
It is in the form
a × 10^b
3 × 10³
3000
3 × 10²
300
3 × 10¹
30
3 × 10⁰
3
3 × 10^-1
0.3
3 × 10^-2
0.03
Example of multiplying standard form?
(3x10⁷) × (2×10⁴)
= (3×2) × (10⁷×10⁴)
= 6×10¹¹
Example of dividing standard form?
(3×10⁷) ÷ (2×10⁴)
= (3/2) × (10⁷×10‐⁴)
= 1.5×10³
What is the equation of a perpendicular straight line
Y = -½x +c
They have negative reciprocal gradients
General form of a quadratic equation?
y = ax² + bx + c
What is the shape of a quadratic line if a > 0?
U shape
