Mike is saving money for a new bike that costs $180.00
​​
​If represents the amount of money he has saved ​so far, which expression represents the amount of money,​in dollars, he still needs to save?
A
180+m180+m180+m
B
180−m180-m180−m
C
180×m180\times m180×m
D
180÷m180\div m180÷m