Percentages and Comparison

100% is the same as saying.....

100/100. For example: 100/100 of this circle is shaded so 100% of this circle is shaded.

Increase of 15% results in having...

115% of original stuff. 1+0.15=1.15

Percentage

A percentage is a part per 100. The symbol is %.

Absolute Change

Actual increase or decrease from a reference value to a new value.

Decrease

Fall in value

100% of any number is...

Just the number unchanged. For example: 100% of 75 is 75

Increase

Rise in value

Relative Change

Size of the absolute change in comparison to the reference value. Can be expressed as a percentage. |end - start|/start

Reference Value

Starting Number or Original Value. Used as base.

Decrease of 90% means you now have...

only 10% left. 1-0.10=0.90 and 1-0.90=0.10

Find relative increase and relative size starting with 2 apples and ending with 3.

|3-2|/2=50% 50% increase in apples. 3/2=150% We now have 150% of our starting apple supply.

What is relative decrease and relative size starting with $5 and ending with $4.

|4-5|/5=20% 20% decrease of money. 4/5=80% We have 80% of our initial cash.

Compare 5 and 4 by % decrease, % increase, % size of each.

|4-5|/5=20%. Decrease 5 by 20% and you have 4. |5-4|/4=25%. Increase 4 by 25% and you get 5. 5/4=120%. 5 is 120% the size of 4. 4/5=75%. 4 is 75% the size of 5.