Unit 2 - number Flashcards
(14 cards)
State the 4 types of numbers + abbreviations
Natural numbers = N; whole numbers used for counting
Integers = Z; positive & negative whole numbers
Rational numbers = Q; a number that can be expressed as m/n were both m and n are whole numbers)
Real numbers = R; all numbers that can be shown on the number line
Improper fraction vs mixed number fraction
Improper - numerator is larger than denominator. E.g. 9/5
Mixed number - e.g. 1 4/5
2 rules of surds
root b x root a = root ab
root a/root b= root a/b
Formula for arithmetic sequences
U(n) (term) = U1 + (n-1)d
U1 is the first term of the sequence
n is the position of the term you want to find out
d is the common difference between each term
Formula for direct and inverse proportion
Direct - y=kx
Inverse - y=k/x
Formula for depreciation
original amount x (1-rate)^n
Formula of profit/loss percentage
difference between original and final price/original price x 100
Formula for compound interest
original amount x (1+rate)^n
Gives interest + original value
Formula for simple interest
original amount x interest as decimal x years
gives only interest
How to convert between m/s and km/h
M/s x 10/36=km/h
Km/h divided by 10/36=m/s
Updating ratios: the ratio of football to volleyball players was 7 : 5 until 2 left football to join volleyball and the ratio become 13:11. Figure out the initial amount of football players.
7x-2 : 5x+2 = 13:11
7x-2/13 : 5x+2/11
77x-22 : 65x+26
12x = 48
x = 4
There were originally 28 football players.
Increase 25$ in the ratio 6:1
For every dollar, you get 6. So 25x6=150
Decrease 24 in the ratio 1:4
For every 4 dollars, you will get 1.
24/4 = 6
Two runners are running towards each other at 4m/s and 6m/s. They are 1km apart. How long will it take before they meet?
- Add speeds together 4+6=10m/s
Divide distance by combined speed 1000m/10 = 100s - It would take 100 seconds before they meet
