Numerical Flashcards
NUMBERS
-
Ordering- ascending =
Increase
Small to big
Ordering - descending =
Decrease
Big to small
Composing & decomposing forms?
Standard and expanded
Rounding decimals - 3.1416
Ten
Hundredth
Thousandth
Ten= 3.1 Hundredth = 3.14 Thousandath = 3.142 Ones = 3
Rounding significant numbers
Count all numbers asked then round
If have 0’s miss the 0 and count significant numbers after
What u know
Addition
Subtraction
Multiplication
Division - the divisor always outside the box
Positive and negative numbers:
++=+
+-=-
-+=+
- - = -
Bodmas?
Brackets Orders (power of roots etc) Division Multiplication Addition Subtraction
% to decimal ?
Decimal \ 100 = percentage
Or move two to the left
8.5%=0.085
% to fraction ?
Always do it out of 100 (dependant on how many numbers ) and then simplify if u can
11/100
62.5 = 625/1000 then simplify = 5/8
Decimal to %
Decimal x 100 = percent
Move 2 to right and put % sign
Decimal to fraction
Decimal / 1
Then multiply both by 10 for every number after decimal point
Simplify and reduce fraction
0.75/1 x 100 = 75/100 = 3/4
Fraction to decimal
Do it as normal long division
Top in box and bottom outside
Fraction to percentage
Long division x 100 and % sign
Items of a fraction
Numerator and denominator
How can you simplify fractions ?
Prime numbers
Greatest common factor
What are prime numbers?
2,3,5,7,11,13,17,19,23,29,31,37
What is a greatest common factor?
Large no into both numbers of fraction
Adding fractions
Ensue denominator both the same
If not - multiply denominators
Add too as usual
Simplify
PERCENTAGES
Important
Different use for perctanges
% difference = looking for average
% change = looking for increase or decrease
% error =looking for over value or undervalued
What to remember for all different percentage methods
Steps 1
- Subtract values from one another first
Step 2 for percentage methods
% change = divide by old value
% error = divide by exact value
% difference = divide by average of values
Step 3 for percentage methods?
% change = + is an increase , - is a decrease
% error = ignore minus sign but if you do have one keep if u want to know value over or under
% difference = ignore minus sign not important
Step 4
Always convert to % = x 100 and add sign
Format for % change
New value - old value / old value x 100
to see percentage increase
Or
New / old
Something to note for percentage change
If the new figure is greater than old - you are looking at the percentage increase
If the old figure is greater than the new - you are looking for the percentage decrease
% decrease?
Old - new/ old x 100
How to find the average normally
Values / amount of values there
Format for % difference?
1st value -2nd value / 1st value - 2nd value / 2 x 100
Format for % error
Approx value - exact value / exact value x 100
Use sign to see if over or under if needed
How to find increase and decrease in a value ? Not same as percentage increase or decrease
Decimal x value
E.g 0.25 x 120 = 30
Then either plus or minus from the original value
Or
For increase
= 1.115 to be quick x the figure
Finding a percentage amount of a cost that already exists?
Finding percentage amount within this figure
Value / decimal
E.g 15% of 180
180/ 0.15
Or 15x 180 / 100
Finding percentage amount - other half that already exists
E.g
56/100 = 10,120
1- 0.56 = 0.44
10,120 / 0.44 = finds the amount within this figure
Simply finding the percentage of values only
Values as a percentage
Smaller Value / bigger value
Square roots ?
1,4,9,16,25,36,49,64,81,100,121,144,
Ratios?
Have the ratio
Simplify it
Ratio can change into a fraction too
1 ration into the amount needed
You times the ratio of 1 amount by the amount needed and simplify
Part to part ratio
Part to whole
Boys : 2:3
All : 2:5
