100 Singapore Dollars

Probability Level 4

Singapore has dollar notes in denominations of $1$ , $2$ and $5$ . How many ways are there to form exactly $\$100$ using just multiples of these notes?

Details and assumptions

The question does NOT state that you must use every denomination. Using 20 $5 notes (and 0 $1 and 0 $2 notes) to form exactly $100 is a valid way.