Is betted a word

Unfortunately 'Betted' is not a Word. As an attempt to conjugate the verb 'to bet', one would not add an 'ed' to the end. To put this verb into the past tense you would simply say 'bet'

An example:

Incorrect - I betted on the races the other day!

Correct- I bet on the races the other day! or I have bet on those races!

Hope I helped.