Number Flashcards
Covering fractions, percentages and ratio
How do you find a PERCENTAGE of an amount?
amount ÷ 100 x %
How do you INCREASE an amount by a given PERCENTAGE?
amount ÷ 100 x %
then ADD it on to original amount
How do you DECREASE an amount by a given PERCENTAGE?
amount ÷ 100 x %
then SUBTRACT from original amount
How do you find a FRACTION of an amount?
amount ÷ bottom x top
How do you INCREASE an amount by a FRACTION?
amount ÷ bottom x top
then ADD it on to original amount
How do you DECREASE an amount by a FRACTION?
amount ÷ bottom x top
then SUBTRACT it from original amount
How do you make a PERCENTAGE?
Make a FRACTION
then convert to PERCENTAGE by x by 100
How do you work out PERCENTAGE CHANGE?
(INCREASE or DECREASE)
Make a FRACTION then convert to PERCENTAGE
difference/starting amount then x by 100
How do you convert a FRACTION to a PERCENTAGE?
MULTIPLY by 100
How do you calculate COMPOUND INTEREST?
amount ÷ 100 x %
ADD to original amount
Repeat starting each year with the new amount you have calculated
How do you solve a RATIO problem?
Write out the ratio and label it
Draw BOXES
DIVIDE number in question by what it relates to (is it the total or a part?)
MULTIPLY what you get by number of boxes related to what the question is asking for
How do you convert a DECIMAL into a PERCENTAGE?
MULTIPLY by 100
How do you convert a PERCENTAGE into a DECIMAL?
DIVIDE by 100
How do you convert a PERCENTAGE into a FRACTION?
%/100
If you are asked to ‘use estimation’ what do you need to do?
Make the numbers ‘nice’ by rounding
Use the rounded numbers to solve the problem
(If using estimation to show a check repeat your method using ‘nice’ (rounded) numbers
