Mr. K's Making Change

 equals 
One two dollar bill equals 2 one dollar bills  equals   + 
One five dollar bill equals 2 two dollr bills plus 1 one dollar bill
or
 equals 
One five dollar bill equals 5 one dollar bills
or
 equals   + 
One five dollar bill equals 3 one dollar bills plus 1 two dollar bill
 equals   + 
One ten dollar bill equals 5 one dollar bills plus 1 five dollar bill
or
 equals 
One ten dollar bill equals 10 one dollar bills
or
 equals 
One ten dollar bill equals 5 two dollar bills
or
 equals   +   + 
One 10 dollar bill equals 1 five dollar bill plus 2 two dollar bills plus 1 one dollar bill
or
 equals   +   + 
One ten dollar bill equals 1 five dollar bill plus 1 two dollar bill plus 3 one dollar bills
or
 equals 
One 10 dollar bill equals 2 five dollar bills
There are many ways to make change for a twenty dollars
 equals   + 
One twenty dollar bill equals 1 ten dollar bill plus 5 one dollar bills plus 1 five dollar bill
or
 equals   + 
One twenty dollar bill equals 1 ten dollar bill plus 10 one dollar bills
or
 equals   + 
One twenty dollar bill equals 1 ten dollar bill plus 5 two dollar bills
or
 equals   +   +   + 
One twenty dollar bill equals 1 ten dollar bill plus 1 five dollar bill plus 2 two dollar bills plus 1 one dollar bill
or
 equals   +   +   + 
One twenty dollar bill equals 1 ten dollar bill plus 1 five dollar bill plus 1 two dollar bill plus 3 one dollar bills
or
 equals   + 
One twenty dollar bill equals 1 ten dollar bill plus 2 five dollar bills
or
 equals 
One twenty dollar bill equals 2 ten dollar bills
There are many ways to make change for a fifty dollar bill
 equals 50 

 equals 25 

 equals 10 

 equals 5 

 equals 2  + 1