How to calculate money from month say if I want to save $30 a month how do I calculate that

Ok ... if u want to save 30 per month ...

30x ... where x is the number of months ... lets say u have saved for 10 months ... sub in 10 for x

30 (10) = 300 ... u should have $ 300

lets say u have saved for 12 months ... x = 12

30 (12) = $ 360