Number Flashcards
Quadratic Sequence Formula
Uₙ = an² + bn + c
U₁ = a + b + c
U₂ - U₁ = 3a + b
a = 2nd difference / two
Rational Numbers
A number that can be expressed as a fraction. ℚ 1/2
Irrational Numbers
A number that cannot be expressed as a fraction. P π
Natural numbers
Positive integers. N.
Integers
Whole numbers, positive and negative. Z
Real numbers
All numbers. R
Finding the nth term of a linear sequence
1) Multiply n by the first difference + adjust
Finding the nth term of a quadratic sequence
1) Multiply n² by half of the second difference
2) Adjust by adding a number or adding 2n or 3n etc.
Finding the nth term of a geometric sequence
??? learn this later bc I can’t be bothered right now
How to work out the Highest Common Factor of two numbers
1) List the prime factors of each.
12 = 2 * 2 * 3
30 = 2 * 3 * 5
2) List the prime factors they have in common
12 = [2 * 3] * 2
30 = [2 * 3] * 5
3) Multiply them togetehr
2 * 3 = 6
6 = HCF
How to find the lowest common multiple of two numbers
1) List the prime factors of each.
12 = 2 * 2 * 3
30 = 2 * 3 * 5
2) Combine the prime factors in a list (but only include the min. possibel amount of a number needed)
2 * 2 * 3 * 5
3) Multiply them togetehr
2 * 2 * 3 * 5 =60
60 = LCM
How to convert recurring decimals to fractions.
0.333333
*10
= 3.333333
-1
= 3
9r = 3
r = 3/9
r = 1/3
Multiplying with standard form
(2 * 10⁴) * (5 * 10⁶)
(25) * (10⁴10⁶)
10 * 10¹⁰
1.0 * 10¹¹
Dividing with standard form
(8 * 10⁶) / (4*10²)
(8/4) * (10⁶/10⁴)
2 * 10²
Percentage increase
((New - Original) / Original) * 100
